Moscow (CNN) The Russian ambassador to the United States said on Friday that Moscow was "open" to a follow-up summit between Russian President Vladimir Putin and President Donald Trump in Washington, four days after the leaders' private one-on-one meeting in Helsinki.

Asked at the Valdai Discussion Club in Moscow to comment on controversial plans by the White House to invite Putin to the US this fall, Anatoly Antonov said: "The Russian side has always been open to possible proposals. We are ready for discussions on that point."

Plans to welcome Putin were announced by White House press secretary Sarah Sanders in a statement on Thursday, hours after Trump tweeted that he was "looking forward" to meeting again with Putin to "begin implementing" issues they discussed during their summit earlier this week.

Trump has been widely criticized for his performance in Helsinki, Finland, at which he was deeply deferential to the Russian leader and lashed out at his own country.

Anatoly Antonov gestures while speaking during a round-table discussion in Moscow on Friday.

"President Trump asked (national security adviser John Bolton) to invite President Putin to Washington in the fall and those discussions are already underway," Sanders tweeted Thursday.

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