Iraq's military says a suicide bomber has struck a military base west of Baghdad.
Officials at the base in Habbaniyah said the bomber, wearing an Iraqi military uniform, killed 16 soldiers and wounded another 50 people.
The Iraqi defense ministry said 17 people were wounded in the blast Thursday, and that no one was killed. The discrepancy could not be immediately reconciled.
Security forces have come under increasing attack in recent days. On Wednesday, a car bomb blast in the northern city Kirkuk killed at least 10 Iraqi security guards. Last week, an attack in Mosul killed two Iraqi policeman and five U.S. soldiers.
The rise in violence, including a spate of bombings in Baghdad earlier this month, has led some U.S. military officials to speculate American troops may not be withdrawn from all Iraqi cities by the end of June, as planned.
A Pentagon spokesman said Thursday that while security forces try to prevent what he called these spectacular and lethal attacks, they are still "very possible in an open" society.