Impossible to prepare for disasters this big, Turkey's president says
Updates from BBC correspondents on the ground: Quentin Sommerville in Antakya, Tom Bateman in Adana, Alice Cuddy in Iskenderun, and Anna Foster in Kahramanmaras
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BreakingDeath toll rising rapidly
Early statements from officials in Turkey and Syria put the death toll over 90, and climbing.
In Turkey, there are at least 23 confirmed deaths in Malatya, 17 in Sanliurfa, six in Diyarbakir and five more in Osmaniye.
Across the border in Syria, at least 42 have been killed, Syria's state news agency reported.
Breaking23 people killed in city of Malatya - governor
Offials in the city of Malatya say 23 people have died in the earthquake.
Another 42 people were injured and 140 buildings have collapsed, said the city's governor.
Scenes from the quake-hit city of Diyarbakir
10 cities affected across the country
Turkey’s Interior Minister Süleyman Soylu said 10 cities in Turkey have been affected by the quake including: Kahramanmaraş, Hatay, Gaziantep, Osmaniye, Adıyaman, Malatya, Şanlıurfa, Adana, Diyarbakır, Kilis.
He said the country's search and rescue teams had been deployed and were at "high alert".
BreakingAt least 17 people killed in earthquake - officials
At least 17 people have been killed so far in the earthquake, local Turkish officials are reporting.
In the city of Osmaniye, the governor confirmed there had been five deaths.
In the city of Şanlıurfa, there have been 12 deaths.
At least 50 buildings have collapsed across the two cities, both in the country's south-east.
Watch: Tremors shake a home in Turkish city Diyarbakir
What do we know so far?
Here is what we know:
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A major earthquake has struck south-eastern Turkey, near the city of Gaziantep.
The quake measured 7.8 magnitude on the US Geological Survey.
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