"We ask security forces in the country to get at least 1,000 meters away from US bases starting on Sunday at 5:00pm (1400 GMT)," said the group.

The vehemently anti-American group's statement came after mortars and rockets hit near the US embassy and a base where US troops are stationed.

Mortar rounds hit an area near the US embassy in Baghdad on Saturday evening, security sources told AFP.

Moments later, two rockets slammed into an Iraqi base where American troops are deployed, security sources said.

The Iraqi military confirmed the missile attacks in Baghdad and on Balad base and said there were no casualties.

Planes from the US-led coalition were heard circulating above their bases in Kirkuk province, AFP's correspondent there said.

A US defence official said the coalition's surveillance capabilities had been redirected away from the Islamic State group to focus on possible new rocket attacks.

The missile attacks appeared to be the first hints of a retaliatory response to the killing by the US of a top Iranian general near Baghdad airport on Friday.

Iran's Major General Qasem Soleimani was killed alongside a top Iraqi paramilitary commander in the US drone attack, which was the most dramatic escalation yet in spiralling tensions between Tehran and Washington.