A senior UN official on Friday denied rebel charges that Angolan troops are fighting alongside forces from the Democratic Republic of Congo in the east of the country.

`We can say with confidence that there are no Angolan nor foreign troops on DRC territory at this point,` said assistant secretary-general for peacekeeping operations Edmond Mulet.

He added rumours that Zimbabwean troops were also involved in the fighting were also `not true.`

`We have no evidence of that, MONUC has not been able to confirm any of that, so for us it is not happening,` he said, referring to the UN Mission in DR Congo (MONUC) force.

Mulet added there may have been a `misconception` because some of the government troops `have been trained in Angola. They are more disciplined, more organized and some of them speak Portuguese.`

Regional leaders at a summit in Nairobi have called for an immediate ceasefire and the creation of humanitarian corridors in the Democratic Republic of Congo.

The Nairobi summit also urged the implementation of existing agreements on the disarmament of rebel groups in the region and beefing-up the UN peacekeeping force`s mandate to provide more robust peace-making capabilities.

Clashes broke out regardless between Congolese troops and renegade general Laurent Nkunda`s rebels around 15 kilometres (nine miles) from the regional capital Goma, scattering thousands of displaced people from a nearby camp.

Nkunda`s Tutsi militia claimed Friday that Angola was supplying troops to back up government forces in the clashes with the rebels.

`There are Angolan troops on the ground. Everybody has seen them. Everybody has heard them,` the rebels spokesman Bertrand Bisimwa told AFP in a telephone interview.

The Angolan soldiers `are wearing Congolese uniforms and speaking Portuguese,` Bisimwa said, without giving details.

Last month a diplomatic source in Kinshasa said the DRCongo could appeal for help from Angola, saying envoys had been sent to Luanda.

Angola did intervene in the DRCongo in 1998 in support of late president Laurent-Desire Kabila, the father of the current head of state Joseph Kabila, against rebels backed by Rwanda and Uganda.