The United States flag flies on the U.S. embassy building in Moscow on March 27, 2018. (Xinhua/AFP)

WASHINGTON, March 29 (Xinhua) -- The White House said on Thursday that Russia's expulsion of U.S. diplomats marks the "further deterioration" in bilateral relationship, warning further retaliation.

In an announcement, the White House said that Russia's move was "not unanticipated," adding the United States "will deal with it."

It added that the expulsion of "undeclared Russian intelligence officers" by the United States and more than two dozen partner nations and NATO allies earlier this week was an "appropriate" response to the poison attack of an ex Russian intelligence officer and his daughter in Britain.

The Russian Foreign Ministry announced earlier on Thursday to expel 60 U.S. diplomats and close U.S. consulate in St. Petersburg in tit-for-tat retaliation for Washington's moves against Moscow over an alleged ex-spy poisoning incident. The 60 diplomats must leave Russia by April 5.

The move came on the heels of President Trump's order on Monday to expel 60 Russian diplomats and intelligence officials in the United States and the United Nations, and close the nation's consulate in Seattle, which aimed to protest and counter Russia's accused involvement of the poisoning attack of former Russian double agent Skripal and his daughter in Britain's southwestern city of Salisbury on March 4.

Russia has denied involvement in poisoning of the former spy and his daughter and vowed further retaliation if U.S. moves forward with sanctions.