Russia’s long-standing ambassador to the United States, Anatoly Antonov, is returning to Moscow, capping a tenure that has seen a marked worsening in relations between the two superpowers. Antonov was to fly home on Saturday, Russian state media said, citing the foreign ministry. The 69-year-old diplomat had served as head of the Russian mission in Washington since 2017. Antonov is seen as a Kremlin hardliner, having served as deputy defence minister before his diplomatic career. In Washington, he is reported to have vigorously defended his country’s invasion of Ukraine, often launching harsh …