WASHINGTON—Republican presidential nominee Donald Trump criticized more than a decade of U.S. foreign policy and cast doubt on assertions that the Kremlin is attempting to meddle in the U.S. elections during a 10-minute interview broadcast on a television network controlled by the Russian government.

Mr. Trump’s interview, broadcast Thursday evening on RT America, came a day after the . His comments drew fire from other Republicans, who have been sharply critical of Russia’s behavior in the Middle East and with neighboring...