The United States said Friday it was expelling two Russian diplomats, a retaliatory step after Moscow kicked out two Americans last month.

"In response to the Russian Federation's specious expulsion of two US embassy Moscow diplomats, the State Department reciprocated by declaring persona non grata two Russian embassy officials operating in the United States," State Department spokesman Matthew Miller said.

Russia said last month that it was expelling two US diplomats for liaising with a Russian citizen who had formerly worked at the US consulate in the far eastern city of Vladivostok, Robert Shonov.

After a previous reduction of diplomats, Shonov started working as a contractor and the United States says he was hired for routine monitoring of publicly available Russian media.

Russia in August announced his arrest on charges of passing along what it called confidential information on Ukraine.

The State Department "will not tolerate the Russian government's pattern of harassment of our diplomats," Miller said in a statement.

"The Department's actions send a clear message that unacceptable actions against our embassy personnel in Moscow will have consequences."

Relations between the United States and Russia have deteriorated sharply since Moscow's invasion of Ukraine last year. The United States has said it sees no point in senior-level talks except on isolated issues such as arranging swaps of prisoners.

Even before the war, the US diplomatic presence in Russia had been sharply reduced after a decree by President Vladimir Putin limiting the hiring of local staff, with Russians seeking US visas often obliged to go to embassies in third countries.

The State Department recently made clear that it would not welcome Putin next month when the United States is host of a summit of the Asia-Pacific Economic Cooperation (APEC) forum, of which Russia is a member.

President Joe Biden said earlier Friday that he held out the possibility of meeting Chinese President Xi Jinping at the summit in San Francisco.

Miller, speaking earlier this week, alluded to charges against Putin by the International Criminal Court, although the United States is not part of the Hague-based tribunal. Putin skipped recent summits in India and South Africa, both far friendlier to Russia than the United States.

"I would be highly surprised if Vladimir Putin, who has been at times reluctant to leave his own borders recently for fear of arrest for the war crimes he's committed... wanted to show up at a meeting in San Francisco," Miller said.

In response, Moscow's ambassador to Washington, Anatoly Antonov, said that the level of representation at APEC "is the prerogative of Russia."