Regular army soldiers have clashed with a group of about 1,000 supporters of a former rebel commander, Colonel Jules Mutebusi, UN officials say. UN peacekeepers have moved to quell recent fighting between the two sides, in which at least 13 people have died.

The latest clash occurred near the airport, north of Bukavu, which the UN has vowed to secure. ?There was an hour or two of fighting (...) between Congolese forces and an advancing column of about 1,000 men,? said UN spokesman Sebastien Lapierre.

He said UN troops deployed at the airport, about 35 km from Bukavu, had not engaged in the clash.

Within the town itself, the peacekeepers have enforced an ultimatum banning supporters of Colonel Mutebusi from carrying weapons.

Under a peace deal agreed last year, all the Congolese warring factions were supposed to unite as a single army.

But violence between Colonel Mutebusi?s group and regular troops broke out on Wednesday evening.

Yesterday gunmen shot dead one of the UN peacekeepers who have been trying to end the fighting.

The UN accused Col onel Mutebusi?s troops of looting and raping civilians. Thousands of people have fled into neighbouring Rwanda. Colonel Mutebusi and many of his troops are from the Banyamulenge ethnic group as are most of those who fled.

The four-and-a-half year conflict in the Democratic Republic of Congo has been described as the worst since World War II.

An estimated 3.3 million people have died as a result of the war making it the ?tragedy of modern times?, according to a report issued by the International Rescue Committee aid agency.

The IRC said that only about 10% of the victims died violently, with the vast majority dying from starvation and disease due to the activities of the various armed groups operating in the country.

?This is a humanitarian catastrophe of horrid and shocking proportions (...) Yet, the crisis has received scant attention from international donors and the media,? says IRC President George Rupp. Africa?s worst ever war began following the invasion of the north and east of the country by Rwanda and Uganda, to, as they said, prevent armed groups attacking them from Congo?s territory.

This brought in armies, which have now left, from other countries to fight on the side of the Congolese Government.

However, ethnic clashes between the Hema and Lendu in the troubled north-eastern province of Ituri remain a potential stumbling block to peace.

The IRC?s report was released as the United States and Britain condemned a massacre of some 1,000 villagers in Ituri province.

The reported massacre near Bunia, came just a day after a peace agreement was signed in South Africa marking the end of 19 months of talks between the government, opposition parties, civil groups, militia and rebels.

The US has called on Uganda to exercise its responsibility to protect civilians in Ituri where the killings occurred and to ensure that no violations of human rights or atrocities are committed.

A Ugandan army spokesman denied any involvement in the massacre, saying his troops had been at least 15 km away.

Both United States and England have also called on all parties in the conflict to cease hostilities immediately and support a committee set up to end the fighting and make the area safe. Reuters news agency reported that people in Ituri were fearful of reprisal attacks.

?This is really hell. We are not secure, even here . Anything could happen,? Emmanuel Ralonji said in Bunia, not far from the scene of the massacres.

<I>?This is really hell. We are not secure, even here. Anything could happen.?</I>