PRAGUE — The long-sought joint peacekeeping force for Darfur, which would combine the existing 7,000-man African Union force with as many as 20,000 additional military personnel and civilian police under U.N. command, has now been approved. But several roadblocks still stand in the way, making it very difficult for the joint A.U.-U.N. mission to bring about a peaceful settlement to the Darfur conflict.

Although U.N. Secretary General Ban Ki Moon pressed the U.N. Security Council to move rapidly to authorize the proposed joint force, member governments remain deadlocked over its mandate.

With the encouragement of Sudan's government, China and Russia have thus far blocked a resolution sponsored by Britain and France that would allow the proposed hybrid force "to use all necessary means" to protect humanitarian workers and other civilians. Sudan's U.N. ambassador has called for a draft whose language is "more Sudan-friendly."