BAGHDAD - 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.

A blast was heard in central Baghdad on Sunday night, Reuters witnesses said and two Baghdad-based diplomatic sources also said they heard the blast.

"A Katyusha rocket fell in the middle of the Green Zone without causing any losses, details to come later," the military said in a brief statement.

The Katyusha multiple rocket launcher is an inexpensive type of rocket artillery that can deliver explosives to a target quicker than conventional artillery, but is less accurate.

The US embassy in Baghdad and its consulate in the Iraqi Kurdish regional capital Erbil evacuated non-emergency staff this week.

President Donald Trump's administration has said it sent additional forces to the region to counter what it called credible threats from Iran against US interests, including from militias it supports in Iraq.

Iran and the United States have both said they do not want war as tensions between them increase.

Reuters