(Adds U.S. comments)
By Joe Bavier
KISANGANI, Congo, May 26 (Reuters) - A small faction of Rwandan Hutu rebels in east Democratic Republic of Congo pledged on Monday to lay down their guns and return home, but the main rebel movement refused and rejected the ceremony as a sham.
The rebel fighters, a breakaway faction of the Democratic Forces for the Liberation of Rwanda (FDLR), made the pledge to government officials and diplomats in the eastern city of Kisangani.
The presence of former Rwandan Hutu soldiers and former Interahamwe militia who fled after taking part in Rwanda's 1994 genocide has destabilised Congo's eastern borderlands and helped spark a 1998-2003 war blamed for 5.4 million deaths.
Congo promised Rwanda last November it would disarm members of the FDLR on its territory, by force if necessary.
This was aimed at complementing a broader U.S.- and European Union-backed process aimed at ending widespread violence in Congo's North Kivu and South Kivu provinces, where fighting has continued despite the official end of Congo's wider war.
Clashes between the army, FDLR fighters, Congolese Tutsi rebels and local Mai Mai militia have forced over half a million North Kivu residents from their homes in the past 18 months.
More than a dozen armed factions signed a ceasefire in January. However, eastern Congo's Rwandan Hutu rebels were not invited to the peace talks and clashes involving Rwandan insurgents have grown more frequent in recent weeks as the army steps up troop deployments near their strongholds.
"We agree to disarm our combatants on Congolese soil to give peace a chance and to avoid the planned phase of military operations," a man identified only as Jean-Michel said at the Kisangani ceremony on behalf of the Rally for Unity and Democracy (RUD), the breakaway FDLR faction.
The RUD, representing only around 300 men out of more than 6,000 FDLR fighters, signed a deal agreeing to a United Nations-monitored programme to disarm and relocate back to Rwanda or away from Congo's border with their homeland.
But another small FDLR faction expected to sign, the FOCA, failed to show up and the main FDLR movement distanced itself from Monday's ceremony, dismissing the RUD as "dissidents who have been excluded from the FDLR for high treason".
In a statement issued on Monday in Paris, the main FDLR movement said it had no representative at the Kisangani meeting and that its mission remained the "liberation" of Rwanda.
U.N. officials who have tried to encourage peace-making in the area said they saw the RUD's pledge as a first step.
"We have to start somewhere," the head of Congo's U.N. peacekeeping mission, Alan Doss, told Reuters.
"It's important that we keep up our efforts to encourage, but also warn the FDLR that it's time to move on."
In Washington, U.S. State Department spokesman Sean Mccormack said in a statement: "The time is now for the Rwandan armed groups in eastern Congo to disarm and repatriate or face consequences of further isolation and condemnation." (For full Reuters Africa coverage and to have your say on the top issues, visit: africa.reuters.com) (Editing by Alistair Thomson & Richard Meares)