Russia ordered the expulsion of the United Kingdom's defense attache in Moscow on Thursday, a move it said was direct retaliation for London expelling Russia's defense attache last week.
The U.K. had accused Moscow's defense attache — a diplomat in charge of military affairs — of being "an undeclared military intelligence officer," a charge Moscow called a lie.
"The defense attache at the British Embassy in Moscow, A. T. Coghill, has been declared persona non grata. He must leave the territory of the Russian Federation within a week," it said.
The ministry warned it could take further measures in response to the U.K.'s decision, which it called "unfriendly," "anti-Russian" and politically motivated.
Relations remain tense between Russia and the U.K., which is a staunch NATO backer of Ukraine and has provided Kyiv's troops with significant military support.
Russia's defense attache, Maxim Elovik, is thought to have been in the U.K. since at least 2014 and has been pictured at wreath-laying ceremonies commemorating Russian war dead.
The U.K. made the decision amid concerns of "malign" Russian activity on British soil, including an arson attack on a Ukrainian-linked business allegedly orchestrated by the Kremlin.
