The Democratic Republic of Congo's M23 rebel group has declared an end to its 20-month rebellion on Tuesday and said it was ready to disarm its troops.
It said it would disarm and pursue a political solution to end the crisis in the east of the country.
The declaration was issued hours after government forces drove the rebels out of their last two redoubts before dawn.
It follows a rapid advance in recent weeks that cornered the insurgents in hills along the border with Uganda and Rwanda.
The U.S. said the declaration was a "significant positive step" for eastern Congo, a region beset during the last 15 years by conflict fuelled by competition for its gold, copper and cobalt as well as cross-border ethnic tensions.
Even so, the real test will be whether the rebels and government both cease their military activities and sit at the negotiating table to thrash out a political deal.
With the M23 defeated, attention will turn to some 20 other armed groups operating in Congo's lawless east.
"The chief of general staff and the commanders of all major units are requested to prepare troops for disarmament, demobilisation and reintegration on terms to be agreed with the government of Congo," M23 leader Bertrand Bisimwa said in a statement.
African leaders had earlier on Tuesday urged the group to renounce their rebellion to allow the signing of a peace agreement with President Joseph Kabila's government. In the distant capital, Kinshasa, hundreds of women marched to parliament chanting songs praising Kabila and the army.
"In a region that has suffered so much, this is obviously a significant positive step in the right direction," Russell Feingold, U.S. special envoy to the Congo and the Great Lakes region, told reporters at a briefing in Pretoria.
Feingold said the issues of an amnesty and reintegration of rebels into Congo's army were key to ensuring a deal did not unravel in the same way that a previous accord signed in 2009 with Tutsi-led CNDP rebels in eastern Congo fell apart.