Protesters angered by recent US air strikes on an Iran-backed Iraqi militia have reportedly broken into the US embassy compound in Baghdad.
US forces are said to have fired tear gas to disperse a crowd that breached the outer wall of the compound, which is in the heavily fortified Green Zone.
One of the guard towers was also apparently set alight.
At least 25 fighters died when the US bombed bases associated with Kataib Hezbollah in Iraq and Syria on Sunday.
The US said it was retaliating for a rocket attack on an Iraqi military base in Kirkuk on Friday that killed an American civilian contractor.
Iraqi Prime Minister Adel Abdul Mahdi said the air strikes had violated his country’s sovereignty and would force it to review its relations with the US.
Kataib Hezbollah’s commander, Abu Mahdi al-Muhandis, warned that the militia’s response “would be very tough on the American forces in Iraq”.
Iran described the attacks as a “clear example of terrorism”.