The Democratic Republic of Congo government on Thursday officially declared a ceasefire in the embattled east following a peace deal signed by warring parties, the defense ministry said.
In a statement, the ministry said "the ceasefire is decreed, this day Jan. 24, 2008, as well as the cessation of hostilities" in Nord-Kivu and Sud-Kivu provinces, under an "act of engagement" signed on Wednesday by all parties to the conflict.
"Formal orders have been sent to the commanders of both military regions," said the text, signed by Defense Minister Chikez Diemu.
The US and Europe hailed the "historic opportunity," but UN staffers said much work remains to be done.
Meanwhile, Rwandan Hutu rebels based in Congo said they were ready to return across the border.
The "act of engagement" was signed by the rebel movement of ex-general Laurent Nkunda, warring militias in the Kivu provinces and the government at the end of a regional peace conference that began on Jan. 6 at Goma, Nord-Kivu's capital.
All parties, including the military, have undertaken to stop fighting immediately, agreeing not to rearm.
"The United States welcomes the signing of a peace agreement with the goal of helping bring lasting stability to eastern Congo and addressing the underlying causes of the conflict," White House spokeswoman Dana Perino said in a statement.
"We call on all parties to ensure urgent implementation of the agreement," she said.
"I am aware of the new challenges ... but nonetheless this agreement is a historic opportunity for the Great Lakes region [of Africa]," EU Development Commissioner Louis Michel said.
Alan Doss, the new chief of the UN mission in Congo, MONUC, said "now we must get down to work."
MONUC, which has already posted 90 percent of its 17,000 peacekeeping troops in the ravaged east, plans to deploy them to create buffer zones in trouble spots vacated by the rival sides, Doss said.
Rwandan Hutu rebels said they were ready to return home, a Congolese foreign ministry spokesman said.
Representants of the Democratic Forces for the Liberation of Rwanda and the Rally for Unity and Democracy (RUD) "are ready to return to Rwanda," said Claude Kamanga, spokesman for minister Antipas Mbusa Nyamwisi, after traveling to Mbuakinua, 160km north of Goma, to meet rebel leaders.