Struggling to rebuild a mission near collapse, the Security Council voted early today to enlarge its force in Bosnia to include up to 12,500 heavily armed troops. The vote was 13-0 with Russia and China abstaining.

The midnight meeting of the council was called by France and came after repeated delays by the United States, which demanded time to examine the costs of the mission.

France and Britain, which have had peacekeepers held hostage by Bosnian Serbs, have been pushing aggressively for the creation of the new force to add muscle to the U.N. mission and give commanders faced with threatening situations another option besides protests and NATO airstrikes.

The resolution increases the size of the U.N. mission by 12,500 soldiers, who will be armed with artillery and mortars. There are some 22,000 peacekeepers already in Bosnia.