The ambassadors’ absense had sent a signal that diplomatic relations between the two countries had hit a new low.
Antonov told Russian news outlets that he was in an “optimistic mood” before returning to Washington after the Biden-Putin summit.
The US Ambassador to Moscow, John Sullivan, is scheduled to return to Moscow in the coming days.
The State Department did not immediately respond when asked about his precise date of return.
The Russian Embassy in Washington said in a statement in March that Antonov was “leaving for Moscow for consultations,” where “during his meetings in the Russian Ministry of Foreign Affairs and other agencies, it is planned to discuss ways to rectify Russia-US ties that are in crisis.”