* At least 90 dead - UN agency says, quoting local sources
* 60 of the civilians, same sources say
* Reports of killing follow Oxfam warning on violence
(Adds further quotes and details)
By John Kanyunyu
GOMA, Congo, May 13 (Reuters) - Dozens of people were killed in attacks in eastern Congo over the weekend, a United Nations aid agency and a U.N.-backed radio said on Wednesday, citing local sources who blamed Rwandan Hutu rebels for the deaths.
A local militia leader confirmed the attack, and aid agency Oxfam warned that joint operations by U.N. peacekeepers and Congolese government forces against the Rwandan Hutu FDLR rebels were causing "untold death and suffering" among civilians.
"We are also getting reports of killings of between 60 and 95 people," said Anneke Van Woudenberg, senior Congo researcher at New York based Human Rights Watch, adding the group had received its information from local chiefs and administrators.
The joint operations follow unprecedented collaboration earlier this year between Congo and former foe Rwanda. They were meant to end years of violence in Africa’s Great Lakes region but have resulted in waves of attacks and displacements.
The U.N.’s Office for the Coordination of Humanitarian Affairs (OCHA) said in a statement local sources told its staff at least 90 people, 60 of whom were civilians, had died in an attack on May 9 near Hombo, in North Kivu province.
Citing local sources and a member of parliament, Radio Okapi, a U.N.-backed radio in Congo, said the rebels, known as the FDLR, had killed at least 62 people, wounded many others and burned houses in the violence near Busurungi.
Bikoi Mukongo Askofu, a member of the Mai Mai local militia in the region, put the death toll at 61.
The Rwandan Hutu rebels have been at the heart much of the region’s violence since 1994, when some of them took part in the slaughter of Tutsis and moderate Hutus in Rwandan before crossing into Congo’s lawless east, where they now roam.
100,000 ALREADY FLED - OXFAM
During the subsequent two wars and a stumbling peace process, Congo and Rwanda long-traded accusations of supporting each other’s rebels until their armies launched joint operations in January to root out the FDLR across North Kivu.
Congo and Rwanda declared the operations a success and the U.N. peacekeeping force is now planning to help Congo continue them elsewhere in the east, where the rebels profit from mines.
But the FDLR have since retaken much of the ground they lost during the offensive and aid workers have long warned that the FDLR was likely to launch reprisals against civilians.
Marcel Stoessel, head of Oxfam in Congo, said on Wednesday the offensive had sparked "a spiral of violence against civilians which has forced 250,000 to flee their homes and caused untold death and suffering that continues to this day".
According to Oxfam, 100,000 people have already fled their homes in South Kivu, even before the new offensive has started.
"By any yardstick it has been a humanitarian disaster, and one the world has ignored ... The U.N. needs to be aware of the full implications of continuing to support military action in the present circumstances," said Stoessel.
U.N. peacekeepers in Congo said they were verifying reports of the massacre and took every effort to protect civilians.
"We are aware of the very delicate situation regarding the protection of civilians ... We are putting a lot of effort into joint planning and protection," Lieutenant-Colonel Jean-Paul Dietrich, military spokesman for the force, told Reuters. (Writing by David Lewis; Editing by Mark John)