Image copyright US Department of Justice Image caption FBI witnesses identified Omar Ameen as a man who took part in the raid in Rawah

An Iraqi refugee has been arrested in the US on suspicion of murdering an Iraqi policeman while fighting for the jihadist group Islamic State (IS).

Omar Ameen, 45, appeared before a magistrate in California on Wednesday in connection with proceedings to extradite him to Iraq to face trial.

An Iraqi arrest warrant alleges that Mr Ameen shot the policeman dead during a raid on the town of Rawah in June 2014.

He arrived in the US five months later and settled in Sacramento.

US prosecutors said Mr Ameen applied to the US for refugee status while living in Turkey after saying he was a victim of persecution and violence.

He was granted refugee status days before the attack in Rawah, which took place as IS seized control of large swathes of western and northern Iraq.

US prosecutors allege that Mr Ameen's family supported and assisted the installation of IS and its precursor, al-Qaeda in Iraq (AQI), in Rawah, and that he was "a main local figure" of both groups.

They say he participated in various activities in support of the groups, including helping to plant improvised explosive devices, transporting militants, soliciting funds, robbing supply lorries and kidnapping drivers.

The Iraqi arrest warrant says that on 22 June 2014, Mr Ameen entered Rawah with a convoy of IS vehicles and drove to the house of the policeman, Ihsan Jasim.

Mr Ameen and five other militants then opened fire at the house, with Mr Ameen fatally shooting the officer in the chest, the warrant alleges.

At Wednesday's hearing, federal magistrate judge Edmund Brennan ordered Mr Ameen to be detained until his next court appearance, accepting the prosecutors' arguments that he posed a danger to the community and a flight risk.

There was no immediate response to the allegations from Mr Ameen's lawyers.

The Sacramento Bee newspaper cited public defenders Benjamin Galloway and Douglas Beevers as saying they were assigned the case minutes before the hearing and that their client was "aware of the basic nature of the charges".

He could be executed in Iraq if convicted of "organised killing by an armed group".