WASHINGTON (Reuters) - A 13-year-old Israeli girl fatally stabbed in her bedroom in the occupied West Bank on Thursday was a U.S. citizen, the State Department said.

The girl, Hallel Yaffa Ariel, was attacked after an assailant climbed a security fence and entered a home in the settlement of Kiryat Arba.

"We have now confirmed that she is a U.S. citizen," State Department spokesman John Kirby said at a news briefing.

(Reporting by Lesley Wroughton; Writing by Doina Chiacu; Editing by Alan Crosby)