Congolese President Joseph Kabila, along with the presidents of Uganda, Kenya and Tanzania, attended a summit in Uganda on the situation in his country, the BBC reported.
The four presidents issued a statement calling on M23 to "stop all war activities and withdraw from Goma" and "stop talk of overthrowing an elected government."
M23 seized control of Goma Tuesday. The group's exact aims are unclear but they have also advanced beyond Goma, taking the town of Sake despite loyalist resistance.
About 500,000 people have been displaced by the rebellion since it began in April.
Kabila has been in talks with Rwandan leaders who have been accused of supplying rebels with weapons, The Christian Science Monitor reported.
Kabila seems unwilling to meet with M23 leaders, experts say.
"Given that the FARDC [Congo's Army] is not strong enough to defeat M23 it's not clear that [Kabila] is in a position to block such an agreement. It may be his only choice," says Laura Seay, a regional expert at Morehouse College in Atlanta. "That said, Kabila only wants to deal with Rwanda, not the M23, as he sees Kigali [Rwanda's capital] as the source of M23's strength."