Congolese Revolution Army (CRA) rebels sit on a truck as they patrol a street in Goma in the eastern Democratic Republic of Congo, soon after the rebels captured the city from the government army.

Goma, Democratic Republic of Congo - Rebels widely believed to be backed by Rwanda seized Goma in eastern Democratic Republic of Congo on Tuesday, parading past United Nations peacekeepers who gave up the battle for the frontier city of one million people.

Fighters from the M23 group entered Goma after days of clashes with UN-backed Congolese soldiers that forced tens of thousands of residents to flee, raising fears of human rights abuses in the sprawling lakeside city.

A senior UN source told Reuters that international peacekeepers gave up defending Goma after the Congolese troops evacuated under pressure from the advancing rebels.

“There is no army left in the town, not a soul... Once they were in the town what could we do? It could have been very serious for the population,” he said asking not to be named.

The M23 rebellion has aggravated tensions between Congo and its neighbour Rwanda, which Kinshasa's government says is orchestrating the insurgency as a means of grabbing the chaotic region's mineral wealth. Rwanda denies the assertion.

“We will continue (resisting) until Rwanda has been pushed out of our country... There will be absolutely no negotiations with M23,” Congolese Information Minister Lambert Mende said, adding that Kinshasa would talk directly only with Rwanda.

UN experts say Rwanda, a small but militarily capable neighbour that has intervened in Congo repeatedly over the past 18 years, is behind the revolt. Congo's mineral wealth, including diamonds, gold, copper and coltan - used in mobile phones - has inflamed the conflict and little has been spent on developing a country the size of Western Europe.

The capture of Goma will also be an embarrassment for President Joseph Kabila, who won re-election late last year in polls that provoked widespread riots and which international observers said were marred by fraud.

Congolese state television reported on Tuesday that Kabila, who has made few public comments on the rebellion in recent weeks, is travelling to Uganda, the mediator in the conflict with the eastern rebels.

Uganda's Junior Foreign Affairs Minister Asuman Kiyingi told Reuters the rebels would not attend the talks.

In the Congolese capital Kinshasa, security forces used tear gas and fired shots in the air to disperse a few hundred youths protesting about the fall of Goma. Residents in Congo's second city, Kisangani, attacked Kabila's local party headquarters.

While conflict has simmered almost constantly in Congo's east in recent years, this is the first time Goma has fallen to rebels since foreign troops officially pulled out under peace deals at the end of the most recent 1998-2003 war.

Hundreds of M23 fighters accompanied their leader Sultani Makenga into Goma, where they were greeted by cheering crowds shouting “welcome” and “thank you”. Before they arrived intoxicated local people had thrown up roadblocks of stones in the largely deserted streets pelted by heavy rain.

“We've taken the town, it's under control,” said Colonel Vianney Kazarama, a spokesman for the rebels. “We're very tired, we're going to greet our friends now.” On Monday, Kazarama had denied the rebels would take the city.

Analysts said it was unclear if M23 would try to make Goma a stepping stone towards Kinshasa, as past rebellions have done, or would use the victory to push the government into talks.

“By making this demand (for talks), the M23 aimed to reduce the crisis to a domestic affair, thereby preventing Kinshasa from internationalising it in order to negotiate a solution at the regional level,” conflict think tank International Crisis Group said in a note.

Goma's fall risked triggering “serious human rights abuses against civilian populations” and had the potential to “relaunch open warfare between the (Democratic Republic of Congo) and Rwanda”.

Before M23 took the city, streams of residents headed for the nearby border with Rwanda. More than 50 000 people who fled earlier fighting abandoned refugee camps around Goma, according to Oxfam.

“With the war, we're suffering so much, I've never seen anything like this in my life,” a woman who gave her name only as Aisha told Reuters, clutching her three children.

While M23 has been accused of abuses in areas it controls, it has also set up an administration that tries to provide basic services such as health care, police training and rubbish removal, residents have told Reuters.

M23 is led by mutinying soldiers who rose up eight months ago, contending that Congo's government violated a 2009 peace deal that was meant to integrate them into the army. Many, however, believe they have since become a front for Rwanda.

Congo analyst Jason Stearns said Rwanda would draw international criticism for the fall of Goma, the capital of Congo's North Kivu province, but also regain influence. Donor nations, some of which had frozen aid to Kigali over its alleged backing for the rebellion, would be forced to accept its role in any negotiated settlement with Kinshasa.

“Donors, and probably the Congolese government, will have no choice but to deal with the rebels and call on Rwanda to help,” he said.

Rwanda accused Congolese troops on Monday of shelling the Rwandan border town of Gisenyi, injuring three people, but it added it would not respond militarily to what it called Congo's “provocation”.

Rwandan Foreign Minister Louise Mushikiwabo said Goma's fall showed there was no military solution and called for talks.

The UN has about 6 700 peacekeeping troops in North Kivu, including 1 400 troops in and around Goma, and the mission had previously promised to defend the town, using attack helicopters to strike rebel advances.

On Tuesday afternoon, armoured UN vehicles still circulated in the streets of Goma, offering help to residents, but troops did not try to block the rebels. No government soldiers were to be seen, with residents saying they left along the main road west toward Bukavu after the rebels began infiltrating.

Wars in the central African nation have killed about five million people and many eastern areas are still afflicted by violence from a number of rebel groups, despite the decade-long peacekeeping mission.

Uganda has blamed the escalation of fighting on a leaked UN report that accused it and Rwanda of supporting Congolese rebels, a document Kampala said damaged its mediation efforts.

Kampala has vigorously denied the UN charges, which emerged in October, and Kiyingi said they had undermined Kampala's mediating role.

“Uganda was mediating in this conflict... and we had managed to restrain M23,” he said. “Then the UN comes up with these wild and baseless allegations against us and we decided to step aside and leave the situation to them and now you see the results.”

Uganda has threatened to pull its troops out of peacekeeping operations in Somalia unless the UN allegations are withdrawn. - Reuters