MOSCOW—Russia’s ambassador has returned to the United States three months after being recalled as tensions rose between Moscow and Washington, according to a tweet from the Russian Embassy on Sunday. Russian President Vladimir Putin and President Joe Biden agreed at their summit in Geneva last week on the return of Russian Ambassador Anatoly Antonov and U.S. Ambassador John Sullivan, who left Moscow in April. Antonov on Sunday boarded an Aeroflot flight to New York and then traveled to Washington. The Russian Embassy tweeted Sunday night that he had returned to his duties. Antonov was called home after a Biden TV interview in which he said Putin was a killer; Russian officials then suggested Sullivan should leave.