The operation of the Russian-controlled International Investment Bank has "become impossible" after U.S. sanctions on its officials and so Hungary has quit the bank, Prime Minister Viktor Orban said on Friday.

He told state radio the United States was an important ally of Hungary but there was a difference of views over the war in Ukraine, and the U.S. had "not given up on its plan to squeeze everyone into a war alliance", a step Hungary would resist. (Reporting by Krisztina Than; Editing by Clarence Fernandez)