Russia on Friday said it declared 18 staff of the European Union delegation in the country as persona non grata and must leave the country in what seems to be a retaliatory move.

"Eighteen employees of the EU Delegation to Russia have been declared 'persona non grata' and will have to leave the territory of the Russian Federation in the near future," the Russian Foreign Ministry said in a statement.

The EU on April 5 declared 19 Russian diplomats personae non grata for "engaging in activities contrary to their diplomatic status" and ordered them to leave host nation Belgium.

The ministry said it summoned Markus Ederer, the EU ambassador to Russia, to inform him of the retaliatory measures.

The statement said the EU bore responsibility for the "consistent destruction of the architecture of bilateral dialogue and cooperation" that had taken "decades" to create.

Western nations have expelled dozens of Russian diplomats amid increasing outrage over Moscow's military campaign in pro-Western Ukraine, and Russia has said that it will respond to all such expulsions.