U.S. says not clear whether Russia has ended use of Iranian air base

WASHINGTON (Reuters) - The U.S. State Department said on Monday it had seen reports that Russia had ended its use of an Iranian air base to carry out strikes against Syrian militants, but it was not clear whether Russian use of the base actually had stopped. Iran said earlier on Monday that Russia had stopped using the air base "for now." Russia said further use of the base would depend on the situation in Syria. State Department spokesman Mark Toner told a briefing the United States was closely monitoring the cooperation between Russia and Iran and "it's not clear to us ... whether their (Moscow's) use of this air base has definitively stopped." (Reporting by Arshad Mohammed; Writing by David Alexander; Editing by Eric Walsh)