The militias attacked eight settlements including a camp sheltering some 3,500 people driven from their homes by the violence in war-torn Darfur, UN spokeswoman Marie Okabe said.
The attacks took place in Darfur's Jebel Moon area on Oct. 29 and 30, forcing thousands to flee, Okabe said.
Secretary-General Kofi Annan urged all parties in the area to end attacks and appealed to Sudan's government to do all it could to protect civilians from such attacks, she said.
Tens of thousands of people have been killed in a 3-12-year revolt in Darfur that has forced 2.5 million people to flee their homes to live in squalid, poorly protected camps.
UN officials say Darfur is one of the world's worst humanitarian crises and that the fighting among government troops, rebels and militias is increasing despite a peace agreement brokered earlier this year by the African Union.
A UN push to deploy a huge peacekeeping mission in Darfur to take over from the poorly equipped and underfunded African Union force now there has been stymied by Sudanese government opposition.

Copyright Reuters, 2006