As hundreds of young men lined up in central Baghdad to hand in documents, the bomber slipped into the crowd in an open area outside Iraq’s former Defense Ministry building, now an army recruitment center and military base. Witnesses and officials at the scene said the death toll could be as high as 75 and that the number of wounded could reach 150.

The attack was the bloodiest in the capital in months. It underscored uncertainty about Iraq’s future and the readiness of its security forces just two weeks before U.S. troop levels are scheduled to drop to 50,000. Nearly six months after inconclusive elections, Iraq is still without a new government, and violent attacks and assassinations are on the rise.