The leaders of the Democratic Republic of Congo and Rwanda have called for a cease-fire in eastern Congo in a bid to end the latest deadly chapter in a three-decade conflict.

Presidents Félix Tshisekedi of Congo and Paul Kagame of Rwanda committed to an “immediate and unconditional cease-fire,” according to a joint statement issued with Qatar, where the two leaders gathered for an unannounced meeting on Tuesday.

They did not say how the cease-fire would be carried out or monitored. But the meeting was the leaders’ most significant step since a Rwanda-backed armed group, called M23, captured eastern Congo’s two largest cities and large swathes of the territory in an offensive that began in January.

“This is the first time a concrete statement is coming from both leaders,” Oluwole Ojewale, a scholar with the Institute for Security Studies who focuses on Central Africa, said in an interview.

Mr. Ojewale said that the United States could have been in a position to convene peace talks, but given that it was not a priority for the Trump administration, Qatar stepped in. But he said the bigger failing belonged to the African Union, whose efforts to bring the two leaders together had been unsuccessful.