* Ceasefire eases risk of regional war
* Rebels drop demand for govt to join ceasefire
* Congolese govt suspicious over offer
By Elias Biryabarema
KAMPALA, Jan 8 (Reuters) - Congolese rebels declared a unilateral ceasefire on Tuesday ahead of a second round of peace talks with the government, boosting hopes for a negotiated end to their nine-month-old revolt.
The announcement marked a relaxation of the M23 rebels' demand last week that the Democratic Republic of Congo government also agree to a truce before troubled negotiations resume.
"We've been for peace ... Today we're declaring that we're in a ceasefire," Francois Rucogoza, the rebels' executive secretary told journalists in the Ugandan capital Kampala, speaking in French through a translator.
"Even if the government refuses to sign a ceasefire agreement we'll continue with the negotiations," he added.
Foreign powers fear the conflict could trigger another regional war in a borderlands zone that has suffered nearly two decades of turmoil.
Successive cross-border conflicts have killed and uprooted millions in the Congo basin since the colonial era, driven by political and ethnic divisions and competition for vast mineral resources.
The Congolese government said it did not have much confidence in the rebel ceasefire.
"We don't think we can see this as a concession from people who don't tend to do what they say. We'll wait and see ... We want to know why (they've made this announcement)," government spokesman Lambert Mende said.
The rebels suggested the United Nations should send an envoy to help them agree a final truce with the government.
"We want Kinshasa to sign a ceasefire with us and if a U.N. special envoy can help achieve that, we think that that's good," M23 spokesman Bertrand Bisimwa told the journalists in Kamlapa.
The M23 insurgents agreed to pull out of Democratic Republic of Congo's eastern city of Goma last month under regional pressure - but a first round of negotiations that followed fell apart amid threats and accusations.
U.N. experts have accused neighbouring Uganda and Rwanda of supporting the rebel campaign, a charge both countries deny.
M23, named after a 2009 peace deal for eastern Congo, at first said it had taken up arms because the Kinshasa government failed to honour its side of the bargain, under which rebel fighters were integrated into the army.
It later broadened its goals to include the "liberation" of all of Congo and the removal of President Joseph Kabila.