The U.N. Security Council has unanimously adopted a resolution that cuts the U.N. peacekeeping force in Congo by 2,000, far less than President Joseph Kabila wanted.

The resolution approved Thursday defies Kabila's wish that the U.N.'s largest peacekeeping force shrink by at least 7,000. It extends the 21,000-strong peacekeeping force for a year and stresses that its exit from Congo should be "gradual and progressive."

The vote comes amid weeks of tension after the U.N. backed out of a planned joint operation with Congo's military against a rebel group, saying the two Congolese generals in charge have been involved in "massive human rights violations."

The U.N. sees the FDLR rebel group's defeat as key to regional security.