Moscow will carefully study the new measures the US announced and will inform Washington of its reaction.

Russian Foreign Minister Sergey Lavrov has expressed regret over the “escalation of tensions” after the US State Department ordered Russia to close several diplomatic offices in the US within 48 hours, RT reports.

Moscow will carefully study the new measures the US announced and will inform Washington of its reaction, Lavrov said.

Russia's new ambassador to the US, Anatoly Antonov, added that it's necessary to look into the situation “calmly and professionally.”

Washington’s move signals that “the US [has] announced the hot phase of the diplomatic war” between the two countries, Chairman of the Duma’s Foreign Relations Committee said.

Despite the “extreme unfairness” of the action, Moscow should not respond “symmetrically,” Leonid Slutsky said. He added that “all efforts should be made to preserve a decent level of diplomatic relations with the US, as a necessary component of global stability.”

This is the latest in a series of tit-for-tat moves by Moscow and Washington.