The attack by at least six rockets came just days after Iran fired ballistic missiles at two bases in Iraq that house U.S. forces, causing no casualties.

The attack comes amid rising tensions in the Middle East between the United States and Iran, which ratcheted up on Thursday after suspected attacks on two oil tankers near the strategic Strait of Hormuz. Iran has denied involvement.

A rocket was fired into Baghdad's heavily-fortified Green Zone, which houses government buildings and foreign embassies, but caused no casualties, the Iraqi military said on Sunday.