Rebels controlling the Democratic Republic of Congo's easten city of Goma have been told to pull out a day after they captured the city, forcing government troops to surrender.
The warning was made in a joint statement released on Wednesday in the Ugandan capital Kampala after DR Congo President Joseph Kabila met his Rwandan and Ugandan counterparts, Paul Kagame and Yoweri Museveni, to resolve the crisis in Goma.
"M23 must immediately stop [its] offensive and pull out of Goma," the three presidents said in the statement.
"A plan to this end is being communicated to them."
The United Nations accuses Rwanda of backing M23 fighters who now control the key eastern town of Goma and take their name after a peace agreement they signed with the Congolese government on March 23, 2009. Kigali denies the charges and Uganda has also dismissed accusations it has aided the rebels.
Rwanda for its part accuses Kinshasa of renewing co-operation with Rwandan rebels based in eastern DR Congo.
'Causes of disturbances'
"The government of the DRC, on its part, has made a commitment to look expeditiously into the causes of disturbances and address them as best they can," the statement added, read out by Ugandan foreign minister Sam Kutesa.
"President Museveni and President Kagame made it clear that even if there were legitimate grievances by the mutinying group known as M23, they cannot accept the expansion of this war," the statement added.
They also cannot "entertain the idea of overthrowing the legitimate government of the DRC, or undermining its authority."
Earlier on Wednesday, thousands of government soldiers and police in the DR Congo surrendered to rebels at a stadium in Goma, the main city in the eastern North Kivu province.
Troops hand over weapons to the M23 rebels
Al Jazeera's Nazanine Moshiri reported on "extraordinary scenes", as the security officers came to hand in their arms.
"[The surrendered officers] didn't have a choice," she said.
The soldiers were told they had a choice either to have peace in the city, or to leave the city, she said.
M23 seized Goma on Tuesday, in a development that raised fears of a new, regional conflict. The capture of the city came after days of fighting with government troops.
The rebels were also reported to have taken control of the town of Sake, on the road to Bukavu.
"The [rebels] arrived an hour ago. Luckily there was no force used. Now they're pretty much everywhere ... The army had already left," Christian Bigebika, executive secretary of an association of local rights groups, told the Reuters news agency by telephone from the town, between Goma and Bukavu.
Rebel forces in eastern DR Congo said on Wednesday they planned to take control of the whole of the vast central African country after they captured Goma - home to more than 1 million people - as well as an international airport.
The city was captured while United Nations peacekeepers looked on.
The peacekeepers were not helping the government forces during Tuesday's battle because they do not have a mandate to engage the rebels, said Congolese military spokesperson Olivier Hamuli.
Our correspondent said people appeared to be frustrated with what they see as the UN's lack of action in protecting them from rebel groups.
According to a UN official, protesters were throwing stones and burning tires at the premises MONUSCO, as the peacekeeping force is known, in at least three cities on Wednesday.
Peacekeepers were on alert and UN staff were re-grouping at secure locations as a precautionary measure, the spokesman said.
A spokesperson for the M23 rebels said they planned to "liberate" the country, by moving to the town of Bukavu and then marching on the capital, Kinshasa, nearly 1,600km away.
The rebels have previously said they are seeking talks with Kabila over the failed implementation of a peace deal that ended a previous rebellion in 2009.
"The journey to liberate Congo has started now ... We're going to move on to Bukavu and then to Kinshasa. Are you ready to join us?" Vianney Kazarama, spokesperson for M23, told the crowd of more than 1,000 in a stadium in Goma.
Thousands of residents have fled across the border to Rwanda, the much-smaller nation to the east which is accused of funnelling arms and recruits to the M23 rebels.
Senior commanders of the group, who the UN have accused of grave crimes including recruiting child soldiers, summary executions and rape, paraded around Goma on Tuesday, waving to the thousands of people who left their barricaded houses to see them.
A UN spokesperson in New York said that the nearly 1,500 UN peacekeepers in Goma held their fire to avoid triggering a battle.
The peacekeepers "cannot substitute for the efforts of national forces" in Congo, Eduardo del Buey, the spokesperson, said.
On Wednesday, the Security Council will review the mandate of the UN peacekeeping force in DR Congo. A resolution adopted on Tuesday by the Security Council asked the UN secretary-general to recommend possible redeployment, and possible "additional force multipliers".
The resolution approved unanimously by the council imposes targeted sanctions, including a travel ban and assets freeze on the M23 rebel group leadership. But it did not name two countries accused by DR Congo of supporting the rebels: Rwanda and Uganda.