Two Katyusha rockets fell inside Baghdad’s heavily fortified Green Zone on Sunday night, with one hitting close to the US embassy.
No casualties have been reported so far.
Social media videos are circulating online showing the moment missile alert sirens rang out in the city.
Since October, there have been several attacks on the Green Zone, which houses several embassies and government buildings. There have also been attacks on US troops in Iraq.
Most of these attacks have not been claimed, but Washington has blamed Iran-backed group Hashed Al Shaabi, a loose coalition of militias officially incorporated into Iraq's state security forces.
Elsewhere in the country on Sunday, Prime Minister-designate Mohammed Allawi withdrew his candidacy for the prime minister post.
Shortly after, President Barham Salih announced that he would begin consultations to choose a replacement within two weeks.
