The United States has called for speedy investigation of an incident in which a 15-year-old American of Palestinian descent appeared to have been badly beaten by Israeli paramilitary police during riots in East Jerusalem.

State Department spokeswoman Jen Psaki confirmed that the teen, Tariq Khdair, was being held by Israeli authorities in Jerusalem and said a consular officer visited him on Saturday.

"We are profoundly troubled by reports that he was severely beaten while in police custody and strongly condemn any excessive use of force. We are calling for a speedy, transparent and credible investigation and full accountability for any excessive use of force," Psaki said.

A video clip circulated on the Internet on Saturday showed two Israeli border police holding down and repeatedly pummeling a masked youth before carrying him away.

The family of Khdair, from Tampa, Florida, who was visiting relatives in East Jerusalem, says he was the target of the punches, although the footage is blurred and the victim cannot be identified as he appears also to be wearing a head covering.

A later part of the video shows Khdair's face with a heavy black eye and swollen lip. He is a cousin of Mohammed Abu-Khdeir, the youth who was abducted and murdered on Wednesday.

The Israeli Justice Ministry said in a statement that the police investigations department was looking into the incident.

Police spokesman Micky Rosenfeld said Khdair was one of six "rioters" caught and detained in the incident.

The Council on American-Islamic Relations in Florida on Friday said Khdair was American-born and called on the State Department to seek the teenager's release.