Ethiopia ? African, Arab, European and U.N. leaders agreed in principle Thursday to a joint African Union-United Nations peacekeeping force for Sudan’s Darfur region.

Sudan, which has strongly opposed allowing U.N. troops in the country, did not give the plan its unreserved approval because officials needed to consult with their superiors, said the country’s U.N. ambassador, Abdul Mahmoud Abdelhaleem.

The force could be as large as 27,000, including the existing 7,000-member AU peacekeeping force in Darfur, but the leaders did not lay out a timetable for the force to begin work, partly because Sudan had some reservations.

U.N. Secretary-General Kofi Annan said the additional personnel could include as many as 17,000 soldiers and 3,000 police officers.

In recent days, pro-government militia forces known as janjaweed have stepped up attacks on villages in Darfur, killing dozens of people, international observers said.