The U.S. military says coalition forces have killed four gunmen and detained 10 other suspects in operations targeting al-Qaida in Iraq forces.

According to the statement, the operations south of Mosul began Thursday and continued into Friday.

Elsewhere, in different districts of the Iraqi capital, Baghdad, the U.S. military said it arrested three wanted al-Qaida in Iraq members.

Earlier, the U.S. military blamed al-Qaida in Iraq for Thursday's double suicide bombing that killed at least 31 people and wounded some 50 others at a wedding party northeast of Baghdad in Balad Ruz.

U.S. military officials say al-Qaida in Iraq is trying to regroup after suffering a blow last year when Sunni tribesmen turned against it.

In another development, the U.S. military says an unmanned American spy plane crashed in Iraq early Friday morning. It says mechanical failure is thought to be the cause. It is not clear where the (MQ-1 Predator) drone went down.

The U.S. military uses spy planes in Iraq to search for insurgents targeting American forces.

Some information for this report was provided by AFP and Reuters.