BAGHDAD (AP) — Iraq's prime minister is denying allegations that drones which targeted Saudi oil pipelines last month could have taken off from Iraq, rather than Yemen.

The attack — claimed by Yemen's Iranian-backed Houthi rebels who are at war with Saudi Arabia — was part of a series of incidents that escalated tensions in the Persian Gulf amid a crisis between Washington and Tehran.

Prime Minister Adel Abdul-Mahdi told reporters in Baghdad late on Tuesday that American officials contacted the Iraqis recently, alleging the drones may have taken off from Iraq.

He said Iraqi military and intelligence haven't confirmed such claims.

The May 14 attack on a Saudi pipeline forced a brief shutdown but caused no casualties.

Iraq hosts more than 5,000 U.S. troops, and is also home to powerful Iranian-backed militias.