The offensive continues with Antonio Dembo in charge

Rui Oliveira, Unita

Unita's representative in Brussels, Azevedo Kangange, said the movement would ask the United Nations and the European Parliament to investigate the circumstances of Mr Savimbi's killing.

He repeated accusations that foreign countries were involved in tracking him down using sophisticated technology.

On Wednesday, it was announced that Vice-President Antonio Dembo is the group's new leader, reports the AP news agency.

Power-struggle

Despite initial hopes that Savimbi's death could end almost 30 years of war in Angola, each side says the other must make the first move.

Mr Kangange said the group was prepared to hold negotiations with the Angolan government as soon as the authorities in Luanda declared a ceasefire.

	Jonas Savimbi Born in 1934 in Bie province Fought the Angolan Government since independence in 1975 US President Ronald Reagan called him a "freedom fighter". Made a failed election bid in 1992 Rarely seen in public Click here for full profile

President Jose Eduardo dos Santos says the government is waiting for positive signs from Unita before it agrees to a ceasefire.

In the meantime, Unita's spokesman in Portugal, Rui Oliveira said: "The offensive continues with Antonio Dembo in charge."

Earlier this week, Unita troops were blamed for killing nine people and injuring another 15 near Malanje, a city 300 kilometres east of Angola's capital Luanda, in an ambush.

As vice-president, Mr Dembo automatically takes over the movement's leadership for an interim period, but analysts have warned that he is likely to face stiff opposition to be leader.

"I don't think he stands a chance. He will most probably be pushed aside by Unita General Secretary Paulo Lukamba, a much stronger man, and the movement could splinter, creating a warlord situation," said Hermann Hannekon, a Pretoria-based consultant on Angolan politics for the Africa Institute of South Africa.

Mr Dembo, 57, is from northern Angola and unlike most Unita fighters is not from Savimbi's Ovimbundo ethnic group, reports AP.

Unita has funded its armed campaign by selling diamonds, while the government has relied on oil revenues.