On 27 December 2019, the K-1 Air Base in Iraq was attacked by more than 30 rockets, killing a U.S. civilian contractor and injuring others. The U.S. blamed the Iranian-backed Kata'ib Hezbollah militia. Later that month, the United States bombed five Kata'ib Hezbollah militia's positions in Iraq and Syria, in retaliation for the presumed Kata'ib attack of 27 December. According to Iraqi sources, at least 25 militia fighters were killed. On 31 December 2019, after a funeral for Kata'ib Hezbollah militiamen killed by U.S. airstrikes, dozens of Iraqi Shia militiamen and their supporters marched into the Green Zone of Baghdad and surrounded the U.S. embassy compound (see article: Attack on the United States embassy in Baghdad). Demonstrators smashed a door of the checkpoint, set fire to the reception area, left anti-American posters and sprayed anti-American graffiti. U.S. president Trump accused Iran of orchestrating the attack.