The UN Security Council has strongly condemned the resumption of rebel attacks in eastern DR Congo.
Meeting in emergency session, the Security Council called for M23 rebels to immediately halt their advance towards the provincial capital, Goma.
It also demanded an end to outside support for the rebels, noting with concern that they were well equipped.
The rebels captured the town of Kibumba on Saturday, despite a bombardment by UN helicopter gunships.
Kibumba is 30km (19 miles) north of Goma, the capital of North Kivu province, which borders Rwanda and Uganda.
North Kivu Governor Julien Paluku said the Congolese army retreated because the insurgents were armed with heavy weapons and backed by Rwandan troops.
Kigali denies the allegation but UN experts say they have evidence of Rwandan support for the rebels, and this week asked the Security Council to sanction senior Rwandan officials as a result.
Ahead of Saturday’s meeting in New York, French ambassador to the UN Gerard Araud said he hoped the Security Council would send a clear signal to M23 rebels to stop their attacks.
“There won’t be any solution without an agreement between the DRC and its neighbours, including Rwanda,” he added.
The fighting is the most serious since July in the mostly lawless but resource-rich eastern DR Congo.
Nearly 500,000 people have fled their homes since April when the rebels mutinied from the army.
On Tuesday, Uganda closed the Bunagana border crossing near Goma.
This followed a request from the DR Congo government, which said the M23 was illegally raising money from people travelling between the two countries to finance its operations.
Last month, a UN panel of experts said Rwanda and Uganda were supplying M23, also known as the Congolese Revolutionary Army, with weapons in what is seen as an on-going battle for control of the region, which is rich in minerals.
Rwanda and Uganda strongly deny the allegation – Rwanda has called on both sides to stop fighting, saying stray bullets have fallen on its side of the border, injuring civilians.
The UN and US imposed a travel ban and asset freeze earlier this week on the group’s leader, Sultani Makenga.
The UN has a large force in DR Congo to help the government establish its authority in the mostly lawless east.