The United States said Monday that its ambassador will return this week to Moscow after two months, voicing hope he will build on last week's presidential summit and reduce potential miscalculations.

The two presidents, Joe Biden and Vladimir Putin, agreed in Geneva to send back top envoys, with Ambassador Anatoly Antonov flying back to the United States on Sunday.

US Ambassador John Sullivan "will return to Moscow this week," State Department spokesman Ned Price told reporters.

"That's in part because we remain committed to open channels of communication with the Russian government, both as a means to advance US interests but also to reduce the risk of miscalculation between our two countries," Price said.

Relations had deteriorated sharply after Biden took office in January with promises to get tougher on Russia, including over alleged election interference, hacking and curbing of dissent.

Sullivan left Moscow in April as the United States and Russia announced a wave of tit-for-tat sanctions and expulsions of diplomats. Antonov, who was recalled in March, said on heading to the United States that he was in an "optimistic mood" and sought "equal and pragmatic relations."

The two presidents have both described their talks in Geneva as frank, with Putin describing Biden, a veteran politician, as a "professional" who was "very attentive" in their talks. Biden defeated Donald Trump, who voiced admiration for Putin even as his administration kept up pressure on Moscow.