Two Russian diplomats have been expelled from Moscow's embassy in Washington, the US State Department confirmed Friday.

The expulsion is in response to Russia's "specious expulsion of two US Embassy Moscow diplomats" last month, a spokesperson said, adding that "the State Department reciprocated by declaring persona non grata two Russian Embassy officials operating in the United States."

"The Department will not tolerate the Russian government's pattern of harassment of our diplomats," the spokesperson said in an emailed statement. "The Department's actions send a clear message that unacceptable actions against our Embassy personnel in Moscow will have consequences."

The retaliatory expulsions come at a time of incredible tension between the two countries as Russia continues to fight in Ukraine following its invasion last year.

In mid-September, State Department spokesman Matthew Miller warned that the US would respond to the expulsion of two US diplomats from Russia "expeditiously."

Last month, US Ambassador Lynne Tracy was summoned to the Russian Foreign Ministry and informed that the two diplomats -- Jeffrey Sillin and David Bernstein -- had been declared as "persona non grata," which means they had to leave the country within a week.

The Russian Foreign Ministry said in a statement that Tracy was given "a harsh demarche with the presentation of an official note regarding the incompatibility with the diplomatic status of the actions of the First Secretary of the US Embassy Jeffrey Sillin and the Second Secretary of the Embassy David Bernstein."

"These persons carried out illegal activities, maintaining contact with Russian citizen (Robert) Shonov, accused of 'confidential cooperation' with a foreign state, who was given tasks for financial compensation aimed at harming the national security of the Russian Federation," the ministry said.

Shonov, a Russian national who had worked for the US Consulate in Vladivostok for more than 25 years, was arrested and charged with "confidential cooperation" with a foreign government, Russian state media outlet TASS reported in May.

Miller denounced the charges as being "wholly without merit" and said Shonov was working for "a company contracted to provide services to U.S. Embassy in Moscow in strict compliance with Russia's laws and regulations" after the Russian government barred the US from employing Russian staff in 2021.

"Mr. Shonov's only role at the time of his arrest was to compile media summaries of press items from publicly available Russian media sources," Miller said in May.