GOMA, Congo—The U.N. Security Council unanimously agreed Thursday to send 3,100 more peacekeeping troops to Congo, while rebels said they remained committed to a pullback from the front lines despite an army attack.

British Ambassador John Sawers said the 15-nation council wants to help contributing nations “as best we can in getting troops on the ground rapidly” once they decide to help out.

Countries have not worked out yet who will contribute the additional troops and police.

Several African nations such as Senegal, Kenya and Angola are among those that could contribute extra troops, council diplomats said, speaking on condition of anonymity because talks are still under way.

The Congo peacekeeping mission, the world’s largest such U.N. contingent, is currently authorized to have 17,000 peacekeeping soldiers and police in the vast Central African nation. Even so, they have been spread thin in an area as large as Western Europe and have been unable to stop the fighting.

Years of sporadic violence in eastern Congo intensified in August, when fighting heated up between the army and fighters loyal to rebel leader Laurent Nkunda, and at least 250,000 people have been displaced.

Nkunda says he is protecting Tutsis from Hutus who fled to Congo after Rwanda’s 1994 genocide. But critics say he is more interested in power and accuse his forces of committing multiple human rights abuses.

Some fear the current crisis could once again draw in neighboring countries. Congo’s devastating 1998-2002 war split the vast nation into rival fiefdoms and involved half a dozen African armies.

On Thursday, rebels said they had fended off an attack from the army, pro-government Mai Mai militias and Rwandan Hutu rebels.