GOMA: Rebels in the Democratic Republic of Congo on Tuesday claimed control of the main city of Goma and its airport, in the mineral-rich east, as President Joseph Kabila urged people to defend the nation's sovereignty.

M23 rebel troops marched silently in single file into the deserted city meeting with little resistance.

In a radio broadcast, rebel spokesman Vianney Kazarama appealed to the population to stay calm and ordered all police and government soldiers to surrender on Wednesday morning at Goma's football stadium.

The UN has around 1,500 “quick reaction” peacekeepers in Goma, part of some 6,700 troops in North Kivu province, backing government forces against the rebels. They were on Tuesday at their base, according to AFP.

Gunfire was heard from the west of Goma and from another area leading to a key road, an AFP reporter on the scene said.

Two vehicles full of rebels drove around the city centre to applause from locals while the body of a DR Congo government soldier could be seen at a major crossroad.

Witnesses also reported that rebel chief Sultani Makenga had arrived in the city. Most locals stayed inside Tuesday with only a few venturing outside.

“What country are we in?” one bewildered woman, who gave her name as Suzanne Bita, told AFP, adding: “The people who have just arrived come from Rwanda.”

Earlier, the rebel spokesman said the group was in control of Goma and the airport and was “pursuing the enemy” who he said were fleeing.

Kabila, in an address to the nation, spoke of a “war” situation and urged the population to fight the rebels. Kinshasa has repeatedly accused neighbour Rwanda of backing the group, made up of soldiers who mutinied in April.

“DR Congo is today confronted with a difficult situation,” Kabila said on national television. “When a war is imposed, one has an obligation to resist. I ask that the entire population defend our sovereignty.”

The rebels are mainly Tutsis, the minority ethnic group of Rwandan President Paul Kagame and the target of the 1994 genocide in that country that claimed at least 800,000 lives.

Kabila was on Tuesday in Kampala for talks on the crisis. As he left for the Ugandan capital, he said he would be “presenting proof against the countries mentioned”.

Responding to the developments, Rwandan Foreign Minister Louise Mushikiwabo said “political dialogue is the only way to resolve the ongoing conflict” and pledged to work towards a “full and durable peace”.

Kinshasa on Monday rejected the rebels' ultimatum for direct talks within 24 hours saying it preferred to “negotiate with Rwanda” which it called “the real aggressor”.

The rebels on Tuesday also took control of the border posts between Goma and Gisenyi, the town on the Rwandan side of the border, another AFP journalist said.

Their advance on Goma marked an escalation in the fighting, which erupted last Thursday after a four-month lull and which has raised fears of a wider conflict engulfing the volatile region.

Earlier on Tuesday, loud explosions shook the area and there were reports of looting in Goma, the regional capital of 300,000 close to the border with Rwanda that is also sheltering tens of thousands of refugees who have fled the clashes.

The international community has raised alarm about the fighting and the UN has accused Rwanda and Uganda of backing the rebels, charges both countries deny.

Washington described the fighting as “an extremely dangerous and worrying situation”.

Last week's fighting came days after US and the UN slapped sanctions on Makenga.

Makenga is accused of atrocities including masterminding killings, rapes, abductions and recruiting child soldiers.

The rebels have said they plan to fight the DR Congo government “until it falls”.

Aid agencies have evacuated staff from Goma and the UN had planned to remove non-essential personnel on Tuesday. The fighting is the most serious since July, when UN helicopters last went into action against the M23.

The rebels mutinied in April after the failure of a 2009 peace deal that integrated them into the regular army.

The mineral-rich east has been the launchpad of rebellions dating back to 1996, with Rwanda and Uganda both playing active or behind-the-scenes roles in much of the warfare.

Two wars that shook the whole of DR Congo between 1996 and 1997 and then again from 1998 to 2002 both began in the Kivu region.

Since 1998 more than three million people are estimated to have died from combat, disease and hunger and 1.6 million have been left homeless.

The former Belgian colony, known as Zaire under the dictator Mobutu Sese Seko who was toppled in 1997, remains one of the world's least developed countries despite a wealth of cobalt, copper, diamonds and gold.

A report by anti-poverty group Oxfam on Tuesday highlighted the toll of the fighting on civilians.