BAGHDAD (AP) - The U.S. command announced Saturday that it was sending 3,700 troops to Baghdad to try to quell the sectarian violence sweeping the capital, and a U.S. official said more American soldiers would follow as the military gears up to take the streets from gunmen.

The 172nd Stryker Brigade, which had been due to return home after a year in Iraq, will bring quick-moving, light-armored vehicles to patrol this sprawling city of 6 million people, hoping security forces respond faster to the tit-for-tat killings by Shiite militias and Sunni Arab insurgents.

The U.S. military hopes more armor will intimidate gunmen, who in recent weeks have become more brazen in their attacks.