KIGALI, Mar 25 (IPS) - Both the rebel Congolese Rally for Democracy (RCD) and the Rwandan government face fresh allegations of carrying out massacres in South Kivu, where 250 civilians were murdered over the weekend.

A dissident Banyamulenge faction claims the Rwandans are now working with their arch rival, Mai-Mai warriors, targetting Banyamulenge civilians.

The Banyamulenge, who sparked the current rebellion in the DRC in August last year, say the violence concentrated on the villages of Burhinyi and Mushinga, around 8O and 4O kilometres south-west of the eastern DRC town of Bukavu.

The Banyamulenge, who migrated to the DRC from Rwanda in the last century, claimed RCD soldiers had killed the civilians indiscriminately.

Unconfirmed reports also say 100 civilians, mainly Banyamulenge, had been killed in an attack on the village of Magunga near Uvira, a town on the border with Burundi, Monday morning.

The reports said the attack had been the work of pro- government Mai Mai warriors hired by the Rwandan authorities, who had hacked their victims to death.

The Rwandan government issued a prompt denial of the reports, dismissing it as a 'fabrication'.

In a statement issued from Kigali this week, the Rwandan government refuted what it described as ''absurd and ludicrous allegations aimed at tarnishing the good image of both the Rwandan government and the Rwanda Patriotic Army (RPA).

The reports were blamed on the Banyamulenge faction which had broken with the rest of the RCD and was accused of running a smear campaign ''to discredit both the RCD and its allies''.

The Rwandan government said it would never cooperate in any way with the Mai Mai, arguing that the militias ''have committed some of the most horrific crimes of genocide and violations of human rights in Congo''. It said the alleged incident at Magunga had simply not occurred.

A senior Rwandan official traced the problems back to a standoff between the RPA and Banyamulenge units in Uvira back in January.

There were reports at the time of serious tensions between rival commanders. The official Rwandan version was that the RPA had stepped in to discipline wayward elements, with three Banyamulenge officers temporarily moved to the RCD headquarters in Goma, on the border with Rwanda.

The Rwandans now acknowledge there is a Banyamulenge faction outside the RCD. But the same government official dismissed it as insignificant.

''This is a very small element'', he said. ''They thought they could intimidate the population so we moved against them. They now want to be heard but theirs is not a force to contend with. They're just doing their own thing''.

The 'faction' in question is now identifying itself as the Republican Forces for Federalism (FRF), a newly-formed movement which is presenting itself as the authentic champion of the Banyamulenge of South Kivu.

Speaking to journalists from Uvira, an FRF spokesman claimed that the RPA was in cohorts with Mai-Mai groups, distributing arms to their fighters while trying to co-opt the Mai Mai leadership.

The spokesman, who introduced himself simply as 'Claude', said the FRF is headed by Muller Ruhimbika, a longtime campaigner for Banyamulenge rights.

Ruhimbika used to work for a local development agency, known as the 'Milima Group'. Milima was suspended by the Mobutu Sese Seko regime in August 1996, accusing it of political lobbying in its campaigns for Congolese citizenship for Banyamulenge.

Ruhimbika was later detained by the Kabila government in May 1998, reportedly being sprung from prison by Banyamulenge soldiers, having earlier been arrested while crossing from Burundi.

Claude said Ruhimbika had fallen out with the RCD and was now in Europe.

He said the FRF was firmly opposed to the DRC leader Laurent- Desire Kabila. ''That man has killed our brothers in Kinshasa and Shaba. We could never work with him'', he said.

But he warned that the Rwandan influence on the RCD had discredited the whole rebellion, and dismissed Banyamulenge RCD supporters like Bizima Karaha, a former minister of foreign affairs, as ''traitors''.

The rebellion in the DRC erupted on Aug 2. after Kabila ordered the remaining Rwandan troops and military instructors, who helped him overthrow the late President Mobutu in May 1997, out of the country.

Since then, the conflict has sucked in Angola, Chad, Namibia and Zimbabwe who are supporting Kabila against rebels backed by Rwanda and Uganda.