U.S. Iran envoy Brian Hook is leaving his post - U.S. official

U.S. Iran envoy Brian Hook is leaving his post, a U.S. official, speaking on condition of anonymity, said on Thursday.

Hook's departure comes as the United Nations Security Council prepares to vote next week on a U.S. bid to extend an international arms embargo on Iran. Some diplomats have said the measure lacks support.

Hook did not immediately respond to a request for comment.