Nairobi/Kinshasa - Around 30,000 people fleeing battles between United Nations-backed Congolese troops and Tutsi rebels are pouring into refugee camps near the eastern city of Goma, the UN refugee agency UNHCR said Wednesday as fierce fighting continued.

UN helicopter gunships and armoured vehicles have been supporting Congolese troops north of Goma, the capital of North Kivu province, as renegade Tutsi general Laurent Nkunda's troops drive for the town.

Nkunda's National Congress for the Defence of the People (CNDP) says it has driven the Congolese army back from the town of Kibumba, which lies about 20 kilometres north of Goma.

However, UN-backed Radio Okapi said Wednesday that UN helicopter gunships had been pounding the CNDP since early morning, forcing them to withdraw from a strategic hill they had been occupying.

The Congolese army also claimed that the CNDP were being forced to give up more ground on Wednesday.

A spokesman for the UN peacekeeping mission in the DR Congo (MONUC) could not be reached to confirm the reports.

The UNHCR said that 20,000 people from a camp for the displaced in Kibumba were amongst those arriving at Kibati, 10 kilometres north of Goma.

Alan Doss, the top UN envoy to the Democratic Republic of Congo, has appealed for more soldiers as the rebel forces threaten to overwhelm government troops and UN peacekeepers.

MONUC has only 6,000 troops in the area - out of a total of 17,000 in the sprawling country - and they are being stretched to the limit.

Doss said in a video conference Tuesday that he needs urgent reinforcements, but that his soldiers would try to prevent major towns falling to the CNDP.

Doss warned that the CNDP forces have split into smaller units in an attempt to infiltrate Goma.

The CNDP has also attacked the town of Rutshuru, 70 kilometres north of Goma, prompting plans to evacuate foreign aid workers based there. However, locals angry at the UN for failing to protect them frustrated the rescue attempts.

"A convoy to evacuate around 50 international humanitarian workers was blocked by the local population and some soldiers yesterday," Ivo Brandau, a spokesman for the UN's Office for the Coordination of Humanitarian Affairs (OCHA) in Congo, told Deutsche Presse-Agentur dpa Wednesday.

"They are in the MONUC base in Kiwanja," he added. "We are looking into the possibilities for today."

Angry demonstrators stoned UN compounds in Goma on Monday and Tuesday. The UN mission said peacekeepers were forced to intervene, and that one civilian was killed in the rioting.

However, Doss defended the peacekeepers, saying it was not possible to have "a soldier behind every tree, on every road or in every market."

The CNDP and other groups in January signed peace accords designed to end sporadic clashes that occurred in 2007, four years after the war, which began in 1998, officially ended.

But the CNDP and government soldiers have been involved in repeated clashes in the eastern North and South Kivu provinces since late August.

UN Secretary General Ban Ki-moon Wednesday called for an immediate end to fighting.

"This fighting must be stopped, and I am deeply concerned about the civilian casualties as well as the increasing number of internally displaced persons," he said at a press briefing in Manila.

Ban said he was consulting with the leaders of DR Congo and neighbouring Rwanda as well as European and African leaders to help resolve the conflict.

The DR Congo government has accused Rwanda of amassing troops on the border with a view to backing Nkunda.

Nkunda says he is fighting to protect Tutsis from armed Hutu groups.

Many Hutus fled to DR Congo after the 1994 massacre in Rwanda, when Hutu militia and military killed an estimated 800,000 Tutsis and moderate Hutus in the space of a few months.

Aid agencies say well over 100,000 civilians have fled the renewed fighting since August, bringing the number of refugees in North Kivu to almost one million.

"The numbers of internally displaced are already huge and it looks like it is going to grow," UNHCR spokesman Ron Redmond said.

A spokeswoman for aid agency Caritas said that a humanitarian emergency was looming.

"It is increasingly difficult to provide food for the IDPs (Internally Displaced Persons) ... some are threatened by starvation and there is also a dangerous lack of clean water," said Ursula Hartwig.

Hartwig said that hordes of displaced were looking for shelter in churches, schools and government buildings in and around Goma.

More than 5 million people are estimated to have died as a result of the long war in the resource-rich nation, most of them due to hunger and disease.

The conflict is often referred to as the African World War owing to the large number of different armed forces involved. (dpa)