Kinshasa - Hundreds of Rwandan rebels in eastern Democratic Republic of Congo are defying a six month ultimatum to disarm, ratcheting up pressure on regional powers and UN peacekeepers to eliminate, once and for all, a force at the heart of two decades of conflict.

Midway to a deadline set by regional leaders, not one Hutu rebel had laid down his weapon and yet rivalries among African nations are undermining the prospect of UN-led military action against insurgents Rwanda has previously hunted down in DRC.

"If it was entirely up to us, we would be fulfilling our mandate to neutralize armed groups," Martin Kobler, head of the 23 000-strong UN mission in DRC, told Reuters, acknowledging the reticence of some political actors but voicing confidence military action would ensue if the Jan. 2 deadline was missed.

Rwandan Hutu FDLR fighters have made the hills and forests of mineral-rich eastern Congo their own during two decades of simmering conflict since they fled Rwanda after the 1994 genocide there by Hutu militia of Tutsis and moderate Hutus.

No progress

Some Congolese military commanders retain close ties to FDLR fighters from alliances forged during a 1998-2003 war, which pitted DRC against an invading Tutsi-led Rwandan force and drew half a dozen regional states into a proxy war.

African leaders gave the rebels six months in July to disarm and either be repatriated to Rwanda or transferred to a transit camp in DRC while they await resettlement in a third country.

On Monday they acknowledged no progress had been made and repeated a vague threat of military force if the deadline was missed. But some regional powers are keener on that than others.

"Everyone wants to go after the FDLR in a different fashion," said Timo Mueller, an independent researcher in eastern Congo. "It will be the FDLR who will benefit from this cacophony of actors."

Political football

Criticised for years for failing to impose peace in DRC, the UN mission has been buoyed by the success of a 3 000-strong Intervention Brigade, launched last year, with the mandate and firepower to take the fight to myriad rebel groups.

In November, with Kigali forced to end covert backing for the rebels, the brigade helped DRC defeat the Tutsi-led M23 rebel group that had seized swathes of territory in North Kivu.

Officials say there are only around 1 500 FDLR gunmen left after the UN peacekeeping mission demobilised over 12 000 in the past 12 years, but their integration in life in eastern DRC makes it hard to separate them from civilians.

Speaking to Reuters from a bush base in eastern DRC, Victor Byiringiro, the FDLR's interim leader, said his fighters would return to Rwanda only through direct talks with Rwanda and not as part of the UN backed repatriation programme.

"To repatriate us to Rwanda is to destroy the FDLR."

Kigali, however, has flatly rejected talks with the rebels, saying the Hutus want to complete the slaughter of 1994.

Frosty ties

Rwanda has repeatedly dispatched troops into its neighbour's east, ostensibly to hunt down Hutu rebels. Kigali has come under intense diplomatic pressure not to interfere in DRC since it was accused by UN experts of backing DRC’s M23 rebels. As a result, it expects UN troops to do the job.

"The FDLR is not a mystery, it's not a complicated armed group to deal with," Foreign Affairs Minister Louise Mushikiwabo told Reuters. "What has to be put forth, in a more visible manner, in a more serious manner, is the political will to get rid of this group."

Other African powers have been more cautious, calling for a political solution that could broach a range of thorny issues, including the fate of the more than 100 000 Rwandan refugees remaining in Congo, whom the FDLR claims to protect.

Tanzania and South Africa - the core of the beefed-up UN brigade - have frosty ties with Rwanda and voiced hesitation over a military solution to the FDLR.

Some Congolese officials also privately say conflict between the FDLR and Rwanda should be resolved through dialogue, amid memories of the alliance between the military and Hutu forces in eastern Congo.

Lambert Mende, a spokesperson for the DRC’s government, denied any wavering in commitment for an offensive.

Jason Stearns, a former UN investigator in DRC, said regional tensions were likely to muddy decision making.

High humanitarian toll

"It's become a bit of a political football in the tense relations between South Africa, Tanzania and Rwanda," he said. "If the FDLR continues to be politicised, then that could also lead to military operations taking a back seat for the moment."

Kobler, the UN chief, said peacekeepers were obliged to obey UN orders and played down any impact of troop contributing governments having misgivings over robust anti-FDLR operations once the Jan 2 deadline expires.

His forces are, for now, committed to a new offensive against Ugandan ADF-NALU rebels accused by the UN and Congolese government of killing dozens of civilians in recent weeks.

Even if operations begin, past experience suggests it will be tricky. Joint Congolese, Rwandan and the UN operations against the FDLR in 2009 were criticised by human rights groups for having a high humanitarian toll amid abuses by both sides.

Ida Sawyer, Human Rights Watch's senior DRC researcher, said that could happen again.

"Some people are scared that more military operations will just bring about more attacks on civilians," she said.

