The United States last month expelled two Russian diplomats in response to an incident in which an American diplomat was attacked by a Russian policeman in Moscow, the state department said Friday.

“On the 6th of June an accredited U.S. diplomat, who identified himself, in accordance with embassy protocols entering the American embassy compound, was attacked by a Russian policeman,” department spokesman John Kirby said in a press briefing.

“The action was unprovoked and it endangered the safety of our employee. The Russian claim the policeman was protecting the embassy from an unidentified individual is simply untrue,” he added.

Russia claimed that the U.S. official was a CIA agent who refused to provide his identification papers and subsequently hit the policeman in the face. “Instead of the CIA employee, who was in disguise, as we understand, it could have been anyone — a terrorist, an extremist, a suicide bomber,” Russian foreign ministry spokeswoman Maria Zakharova said, according to the Associated Press.

A video of the altercation was released earlier this week by the state-owned NTV network. It shows a man exiting a taxi in an area reported to be the embassy entrance and walking toward the entrance from where the guard runs out and tackles the man.

“On June 17, we expelled two Russian officials from the United States in response to this attack,” Kirby reportedly said, without giving further details about the decision.

The U.S. said it had raised its concerns regarding the alleged harassment of U.S. diplomats in Russia directly with President Vladimir Putin. Kirby revealed Thursday that U.S. Secretary of State John Kerry had also raised the incident with Russian Foreign Minister Sergei Lavrov on June 7 and the governments were supposed to hold talks privately.

The bilateral ties between the two countries have been steadily deteriorating in recent years with U.S.-backed sanctions against Russia after its annexation of Crimea and the countries’ opposing stands with regards to the war in Syria.

Kirby said the Russian security services have “intensified their harassment against U.S. personnel in an effort to disrupt our diplomatic and consular operations.”

“We’ve privately urged the Russian Government to stop the harassment of American personnel in Russia, and as I said before, the safety and well-being of our diplomatic and consular personnel abroad and their accompanying family members are things we take very, very seriously,” he added.