By PHIL STEWART | REUTERS

BAGHDAD: The United States will take unilateral action when needed to deal with the threat to American troops in Iraq from militias armed by Iran, US Secretary of Defense Leon Panetta said on Monday.

US forces officially ended combat operations in Iraq last August but have come under increasing fire in recent weeks. Fourteen US service members were killed in hostile incidents in June, the highest monthly toll in three years.

US officials blame militias armed by Iraq’s neighbor Iran for most of the recent attacks.

At least three US service members have been killed this month, including one on Sunday, the day Panetta arrived in Baghdad on his first trip to Iraq as defense secretary.