The US State Department said on Thursday it was troubled by a video that showed an radical Iraqi group threatening to kill the American citizen Micah Garen who had been missing in Iraq.

"We have obviously seen the video by those purporting to hold American citizen Micah Garen. We are obviously troubled and concerned by this development," State Department deputy spokesman Adam Ereli said at a news briefing.

"We are doing everything possible to ascertain his whereabouts.We continue to remain in contact with Mr. Garen's family and his fiance and provide all possible assistance to them," Ereli said.

Ereli said the United States took the threat information seriously.

"We use it, we try to act on it. Our objective is to bring about the safe release of this innocent victim of terror, and we will continue to do everything we can to bring about that," Ereli said.

Micah Garen, 36, was abducted Saturday along with his Iraqi interpreter in a Nasiriyah marketplace in southern Iraq.

Source: Xinhua