BAGHDAD (AP) — Iraqi police say gunmen have killed 13 soldiers on an army base in the country's northeast, bringing the nationwide death toll to 82 in the single bloodiest day so far this year.

Two senior police officials said the gunmen arrived at dawn Monday at the military base in the town of Udaim in three vehicles and began shooting at soldiers. No others were wounded.

The police spoke on condition of anonymity because they were not authorized to speak to the media.

The attack was one in a wave of violence across the country that left 82 dead.

It was the single deadliest day in Iraq since the U.S. military left last December.

And it comes days after the leader of al-Qaida in Iraq warned that the militant group is regrouping.