Moscow has expelled 18 employees of the European Union's delegation to Russia in retaliation for the expulsion of 19 Russians from Brussels earlier this month, the Russian Foreign Ministry said in a statement.
"Eighteen employees of the EU Delegation to Russia have been declared 'personae non gratae' and will have to leave the territory of the Russian Federation in the near future," the ministry statement on April 15 said.
Russia's Foreign Ministry said it had summoned the EU ambassador to Russia, Markus Ederer, and informed him of the retaliatory measures.
"The Russian side declared that the EU is responsible for the consistent destruction of the architecture of bilateral dialogue and cooperation that had taken decades to form," the ministry said.
The EU diplomats must leave Russia as soon as possible, the ministry added.
The European Union decried the decision as unjustified.
"The European Union deplores the unjustified, baseless decision of the Russian Federation to expel 18 members of the Delegation of the European Union to the Russian Federation," the EU's diplomatic service said in a statement.
"There are no grounds for Friday's decision by the Russian authorities beyond being a pure retaliatory step. Russia's chosen course of action will further deepen its international isolation," it said.
The EU on April 5 declared the 19 Russian diplomats personae non gratae for "engaging in activities contrary to their diplomatic status" and ordered them to leave host nation Belgium.
Western nations have expelled dozens of Russian diplomats over Moscow's unprovoked invasion of Ukraine, and Russia has said that it will respond to all such expulsions.