Russia said on Wednesday it was ordering U.S. Embassy staff who have been in Moscow for more than three years to fly home by January 31, a retaliatory move for a U.S. decision to limit the terms of Russian diplomats.
The step, the latest in an escalating diplomatic row, comes after Russia's ambassador to the United States said last week that 27 Russian diplomats and their families were being expelled from the United States and would leave on January 30.
Washington says the diplomats were not expelled but had been in the country for longer than a new three-year limit.
"We ... intend to respond in the corresponding way. U.S. Embassy employees who have been in Moscow for more than three years must leave Russia by January 31," Foreign Ministry spokesperson Maria Zakharova told a briefing.
The RIA news agency reported that Zakharova said the new U.S. rules meant Russian diplomats who had been forced to leave the United States were also banned from working as diplomats in the United States for three years.
"Before July 1 next year, unless Washington waives the three-year rule and compromises, more [U.S.] workers [in Russia] will leave in numbers commensurate with the number of Russians announced by the State Department," she said.
Washington informed Russia over a year ago that its diplomats would be allowed to stay for only three years but could be replaced by other diplomats, according to a State Department spokesperson.
"I want to be clear, this is not an expulsion," the spokesperson said, adding the rule change was designed to have Russia rotate its diplomats with similar frequency to that of the U.S. Embassy in Moscow.
Further reductions in U.S. Embassy staff in Moscow would put pressure on an operation that Washington has already described as being close to a "caretaker presence" amid tit-for-tat expulsions and other restrictions.
The embassy is the last operational U.S. mission in the country after consulates in Vladivostok and Yekaterinburg were closed, and it has shrunk to 120 staff members from about 1,200 in early 2017, Washington says.
Russian Deputy Foreign Minister Sergei Ryabkov said it was not too late for Washington to stop Moscow from following through on the new expulsions if it abandoned its own plans to force out Russian diplomats.
Ties between Washington and Moscow, at post-Cold War lows for years, are under pressure due to a Russian troop buildup near Ukraine.