Rushdi Abualouf
Gaza correspondent

Image source, Reuters

The succession process could be quite chaotic and one that isn't decided quickly. It could pave the way for more extremist pro-Iran figures leading Hamas.

One of the people in the frame is Yehiya Sinwar – the group's current head in the Gaza Strip. He is believed to be the mastermind of Hamas's deadly attack on Israel on 7 October 2023.

And there are at least two more senior Hamas officials who might step up to succeed Haniyeh.

Khaled Meshaal, seen as less extreme, could be preparing to launch a leadership challenge. In fact, he had led Hamas for years before Haniyeh – but has always had difficult relations with Iran.

Another potential candidate is Zaher Jabareen, who is responsible for Palestinian prisoners in Israeli jails. He could play a key role in ongoing negotiations on prisoner swaps with Israel.

All three Hamas figures are current Haniyeh's deputies.

Read more: Who are Hamas's most prominent leaders?

What could Iran's response mean for the region?published at 14:03

14:03

Kasra Naji
Special correspondent, BBC Persian

The immediate concern now is Iran’s response and what shape it might take – and what such a response would mean for tensions in the region.

In April, Iran fired more than 300 missiles and drones at Israel in reaction to the killing of a top commander of its Quds Force in Syria and six other members of the revolutionary guards at its consulate building in the Syrian capital, Damascus.

The action was unprecedented in its scope and seriousness. Now Iran could unleash an attack of similar kind on Israel.

Iran also could ask its proxy militias in the region to step up their attacks on Israel. Hezbollah will have a reason of its own to escalate its cross border missile war with Israel.

Already there are commentators in the region who believe that the tensions between Israel and Hezbollah will reach a new high, with a full-scale war between the two breaking out a distinct possibility.

Will all this lead to an all-out war in the region? It's difficult to say. It's clear that no one wants such an outcome at the moment, but wars are not always the result of calculated risks.

Israel and Iran have been engaged in a years-long shadow war – attacking each other's assets without admitting responsibility.

Those attacks have ratcheted up considerably during the current war between Israel and Hamas, in Gaza, sparked by Hamas's attack on nearby Israeli communities last October.

In April of this year, Iran launched a direct missile attack on Israel, saying it was retaliation for an Israeli strike on the Iranian consulate in the Syrian capital Damascus, which killed senior military commanders.

The two countries were allies until the 1979 Islamic revolution in Iran, which brought in a regime that has used opposing Israel as a key part of its ideology.

Now, Iran does not recognise Israel's right to exist and seeks its eradication. Israel believes Iran poses an existential threat as evidenced by Tehran's rhetoric, its build-up of proxy forces in the region – including the Lebanese Shia militant group Hezbollah – and its funding and arming of Palestinian groups, including Hamas.

• Read more on this here

Countries and groups affiliated with Iran have been continuing to respond to the death of Hamas's political leader, Ismail Haniyeh. As a reminder, Israel has not commented on claims it was responsible.

Here's a look at some of the reaction we've seen so far:

• Hamas's armed wing say the killing of Haniyeh will have major repercussions
• Iran's Revolutionary Guards say it "will be met with a harsh and painful response" - echoing threats from Iran earlier
• But at the same time, Iran's vice-president is quoted by state media as saying his country has no intention of escalating the Middle East conflict
• Hezbollah sends its condolences and says it will make Iran-aligned groups more determined to confront Israel
• Egypt echoes some of Qatar's comments, saying the strike suggests Israel lacks the political will for de-escalation

• And Iraq calls Haniyeh's killing a "serious violation" that could destabilise the region

Paul Adams
Diplomatic correspondent, in the West Bank

With the shops closed and the midday sun beating down, Palestinians took to the streets in the centre of Ramallah to vent their anger.

Ramallah, home of the Fatah-dominated Palestinian Authority, is not exactly a stronghold of Hamas. The demonstration wasn’t huge – a few hundred people at most.

But no one should doubt the strength of feeling, the sense of shock and anger, generated by the killing of Ismail Haniyeh. The green banners of Hamas were held aloft, alongside – but outnumbering - the black, white, green and red, Palestinian flag. Children rode on their fathers’ shoulders, carrying toy machineguns.

Defiant chants echoed through the streets. But there’s real anxiety here too. Palestinians feel that a wider conflict might be looming, one that could engulf the West Bank. They feel that this is what the right-wing government of Benjamin Netanyahu wants.

“I think the Israeli government has just committed one of the gravest mistakes in its life,” the moderate Palestinian politician and former presidential candidate Mustapha Barghouti told me earlier, as he prepared to walk with the demonstrators.

“This was a political, criminal act and if they think that this act of assassination will break the Palestinian resistance, they are absolutely wrong.”

Image source, EPA

Rushdi Abualouf
Gaza correspondent

This morning I spoke to three senior Hamas officials, and they were all in a state of shock.

They gave different - quite confusing - accounts as to what exactly happened in the Iranian capital, Tehran, in the early hours of today.

They said they were very surprised by the attack, that Haniyeh had visited the city many times before and must have felt safe going there.

And the question now arises as to who should be responsible for this major security failure - and was it the right decision for Haniyeh to be in Tehran in the first place?

Jaroslav Lukiv
Live reporter

Image source, EPA

It's coming up to eight hours since news first broke of Haniyeh's death - and reaction is still coming in. Here's what's been happening:

• Ismail Haniyeh killed: Hamas says its political leader was killed in an Israeli attack in Iran's capital Tehran early on Wednesday - more on who he was here
• What happened? According to Iranian state media, an air strike hit a building for war veterans in Tehran where Haniyeh was staying at around 02:00 local time
• Who is responsible? Israel has been blamed but is yet respond to the accusations. It has previously vowed to eliminate Hamas's leaders following the group's 7 October attack
• Iran vows revenge: Iran's president - Hamas's most important backer - promises to avenge Haniyeh's death
• Condemnation: There has been widespread criticism of the attack from across the Middle East, amid fears of further escalation. (Will things escalate? Our security correspondent gives his take)
• Ceasefire talks: And there are also concerns for what it means for ceasefire talks - as Haniyeh was a key figure in negotiations. Qatar's PM says how can talks succeed when one side targets another
• Elsewhere: The attack in Tehran comes hours after Israel claimed it killed a senior commander of the powerful Hezbollah militant group in Lebanon. Hezbollah confirmed the strike happened - but says it's still searching rubble for the commander

Frank Gardner
Security correspondent

Clearly this an extremely dangerous moment for the Middle East.

Iran has vowed revenge and the last time that happened it sent a barrage of hundreds of missiles and drones at Israel, which then responded with a calibrated missile attack close to Iran’s nuclear facilities. It took frantic diplomatic intervention to dissuade Israel from hitting harder.

But not every incident like this leads to escalation.

In 2020 then-President Trump ordered the assassination of Iran’s most powerful military commander Gen Qasem Soleimani, in Baghdad.

There were furious calls for revenge but not much happened.

In 1986, then-President Reagan ordered an airstrike on Libya in retaliation for the bombing of a Berlin discotheque.

There were fears the Arab world would erupt in flames but it didn’t.

This time though, there are many more parties involved: a seemingly endless Israeli operation in Gaza; Hezbollah in Lebanon wounded by the assassination of a commander; the Houthis in Yemen vowing revenge for an Israeli airstrike; and Iran humiliated by a missile strike on a guest right in the heart of its capital.

We're just hearing a bit more from US Secretary of State Antony Blinken.

"This is something we were not aware of or involved in," he says.

Image source, Getty Images

More now on what's at stake for ceasefire talks.

US Secretary of State Antony Blinken says he won't speculate on what impact today's news might have - but he stresses the importance of continuing to push for a ceasefire.

"Nothing takes away from the importance of getting to the ceasefire, which is manifestly in the interest of the hostages and bringing them home," he says during an event in Singapore.

Blinken says Palestinians "are suffering terribly every single day, children, women, men in Gaza caught in this crossfire that Hamas is making".

Rushdi Abualouf
Gaza correspondent

As we've just reported, Haniyeh's killing may also have a wider impact on the ongoing efforts to end the Israel-Hamas war.

In December, Hamas briefly suspended ceasefire talks with Israel following the killing of Haniyeh's deputy in the Lebanese capital, Beirut.

And this latest attack in Tehran could make it harder to reach a truce as Hamas will now be focused more on finding Haniyeh's successor in what could be a complicated and prolonged process.

Qatar - which has been brokering ceasefire talks between Hamas and Israel - has suggested Haniyeh's killing could jeopardise the talks. Haniyeh played a significant role in the negotiations.

"Political assassinations and continued targeting of civilians in Gaza while talks continue lead us to ask, how can mediation succeed when one party assassinates the negotiator on other side?" Qatar's PM says.

"Peace needs serious partners and a global stance against the disregard for human life."

Israel has not responded to claims that it's behind the attack.

Hugo Bachega
Middle East correspondent, in Beirut

Away from Haniyeh’s death for a moment, I'm here in Beirut near to where Israel struck a building in a Hezbollah stronghold yesterday. They claimed to have killed a senior commander, Fuad Shukr.

The area in Dahiya in the city’s southern suburbs has been cordoned off, and there is a heavy presence of members of the group and soldiers from the Lebanese army.

Shops are closed and emergency services are still searching through the rubble of the building hit.

It is believed that this is the first time Hezbollah has been targeted in its stronghold in Beirut, but this area was hit before in the current crisis - in January, an attack killed a top Hamas official.

In a statement this morning, Hezbollah says the senior commander targeted was in the building when the attack happened yesterday, just before sunset, but did not confirm he was killed, as announced by the Israeli military.

We still do not know how Hezbollah will respond but a retaliation is all but certain.

Jeremy Bowen
International editor

I first met Ismail Haniyeh back in the late 1990s, when he was a rising Hamas official in Gaza.

His family has already been targeted by Israel since 7 October - sons and grandchildren who were travelling with him, killed by the Israelis.

What is interesting about this is that Haniyeh was not a figure that lived in hiding, like the leaders of the military wing.

Assuming it was Israel who killed him, and I can’t say who else it might be - and they haven’t commented as yet - why are they doing it now when they must have had some chances in the past?

It was not politically possible for them to kill him in Qatar. Killing him in Iran though, does send a message about Israel’s reach, a message that no one is safe.

Haniyeh was involved in the ceasefire and hostage release talks, so this is not going to make those any easier.

Haniyeh had been in Iran to attend the inauguration of new President Masoud Pezeshkian, who was elected earlier this month.

He was usually based between Qatar and Turkey.

The reaction is continuing to come in from the region and beyond.

Jordan says it condemns "in the strongest terms Israel's assassination" of the Hamas leader - and that it will lead to "more tension and chaos in the region".

A reminder - Israel has not commented on whether it was behind the attack.

It was also condemned by Lebanon - whose Prime Minister Najib Mikati also warned of a serious escalation in the wider region at an urgent meeting of his cabinet this morning.

And China's foreign ministry says it "resolutely opposes and condemns the assassination" and is "deeply concerned" about more turbulence in the region.

Spokesman Lin Jian adds "a comprehensive and permanent ceasefire" should be reached in Gaza.

Raffi Berg
Middle East online editor

The killing of the overall leader of Hamas is seismic in terms of both the target and where it happened.

Weeks after the unprecedented 7 October attack by Hamas on Israel, Israeli Prime Minister Benjamin Netanyahu said publicly that he had instructed the Mossad – Israel’s intelligence agency – “to act against the Hamas leaders wherever they are”.

Ismail Haniyeh was in Tehran when he was killed, reportedly by an aerial strike.

The fact that it happened not in Qatar where Haniyeh lived surrounded by security, but inside Iran – Hamas’s most important backer – sends a signal that nowhere is off-limits if it is indeed confirmed that Israel carried out the strike, and that it is capable and willing of acting right under the nose of its most mortal foe.

Haniyeh’s death comes just two weeks after Israel targeted Hamas’s number two, its elusive military chief Mohammed Deif, in Gaza. Indications are that he was killed.

The removal of Hamas’s top political and military leaders is the biggest blow to the group on an individual and operational level since the war began.

Iranian President Masoud Pezeshkian says he will make Israel "regret" the "cowardly" killing of Haniyeh, adding that Iran would "defend its territorial integrity, honour pride and dignity".

In a statement quoted by AFP news agency, the Iranian president described Haniyeh as a "brave leader".

The Hamas political leader, who is based in Qatar, was visiting Tehran to attend Pezeshkian's presidential inauguration ceremony.

Iran's supreme leader, Ayatollah Ali Khamenei also says that avenging his death is "Tehran's duty", adding that Israel - who has not claimed responsibility - had provided the grounds for "harsh punishment".

Image source, Reuters

Paul Adams
Diplomatic correspondent, reporting from Jerusalem

While details of the attack slowly emerge, its political consequences are also coming into focus.

The most obvious is the likely damage to fragile efforts to negotiate a ceasefire in Gaza.

Ismail Haniyeh may not have been in charge of day-to-day events on the ground in Gaza - that’s the domain of the military commander Yahya Sinwar - but as the Hamas leader in exile he was a critical interlocutor in negotiations brokered by Qatar, the US and Egypt.

American officials had recently suggested that ceasefire negotiations might soon succeed, although a meeting in Rome last weekend did not result in a breakthrough.

But it’s extremely hard to see how any progress can be made in the immediate wake of the assassination of Haniyeh.

All of which begs the question: if this was, as everyone assumes, an Israeli operation, why was it carried out?

Beyond the desire to exact revenge on anyone associated with Hamas, what was Israel hoping to achieve?

Turkey’s foreign ministry has already summed up the likely reaction of many in the region - accusing Benjamin Netanyahu of having "no intention of achieving peace".

We're still getting more reaction coming in to Haniyeh's death.

In a statement, Qatar's foreign ministry described it as a "heinous crime, a dangerous escalation and a flagrant violation of international and humanitarian law".

It warned that "this assassination and the reckless Israeli behaviour of continuously targeting civilians will lead to the region slipping into chaos and undermine the chances of peace".

Israel hasn't yet responded to the death.