File photo of Paul Kagame.

Regional leaders met here Saturday to try to resolve the crisis in DR Congo, where a rebel advance has sparked fears of a wider conflict breaking out in the chronically unstable east of sub-Saharan Africa's largest country.

But the summit was proceeding without a key player, Rwandan President Paul Kagame, whose country the United Nations has accused of backing the DR Congo rebels, a charge that Rwanda denies.

Kagame had been expected to attend, but a Ugandan foreign ministry official told AFP shortly before the meeting started that the president was not coming and would instead be represented by his foreign minister, Louise Mushikiwabo.

No reason was provided for the absence.

The international community has raised alarm over the lightning advance by the M23 rebels in DR Congo's mineral-rich but underdeveloped eastern Kivu region, where the insurgents seized the regional capital of Goma and a neighbouring smaller town in less than a week.

The advance has displaced tens of thousands of civilians, sparked warnings of a humanitarian disaster, and raised fears that a wider conflict could again erupt in the area, the cradle of two wars that shook DR Congo over the past several decades.

DR Congo President Joseph Kabila flew in for Saturday's summit in Kampala that will also include the presidents of Uganda, Kenya and Tanzania.

The leaders will discuss a plan that army chiefs had been working on Friday night to oversee an M23 pull-out from Goma, Ugandan Foreign Minister Sam Kutesa told journalists ahead of the meeting.

“A mechanism or plan is being worked out to get them to withdraw,” Kutesa said.

Kutesa called on the Congolese government forces to halt attacks on M23 in order to allow any peace plan to work.

“It is important that if they (the rebels) have been asked to halt then they should not be attacked,” Kutesa said.

An M23 delegation was also in Kampala, but not at the summit, which is officially reserved for the nations of the 11-member International Conference on the Great Lakes Regions.

M23's political leader Jean-Marie Runiga Lugerero expects to hold separate talks with Ugandan President Yoweri Museveni later in the day.

“There has not been a meeting yet. We are still waiting,” said Rene Abandi, head of external relations for M23's political wing.

The rebels captured Goma, the capital of North Kivu province, on Tuesday after less than a week of fighting before taking the key town of Sake 20 kilometres (12 miles) to the west the next day.

Reports on Saturday said the situation was calm but tense in both towns.

The DR Congo president Kabila had met with the leaders of Rwanda and Uganda immediately following the fall of Goma and the three leaders issued a joint statement urging the rebels to pull out of the city.

The M23 has refused to withdraw unless Kabila agrees to direct peace talks with the group.

The UN has also accused Uganda of backing the M23 rebels, charges that Uganda denies.

Rwanda's president Kagame was due to hold talks with his counterpart from the Congo Republic, Denis Sassou Nguesso later on Saturday, according to sources in both capitals.

Members of Sassou's delegation had already arrived Friday in the Rwandan capital.

The M23 was launched by former fighters in an ethnic Tutsi rebel group that was integrated into the military under a 2009 peace deal whose terms the mutineers say were never fully implemented.

The two DR Congo wars of 1996-2002 both started in the volatile east of the country. -Sapa-AFP