UPDATE 2-Dozens killed in Congo's east - UN citing sources

* 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.