Moscow has expelled 18 employees of the European Union’s delegation to Russia in retaliation at Brussels’ expulsion of 19 Russians earlier this month, the foreign ministry said in a statement on Friday.

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. Russia’s foreign ministry said in its statement that it had summoned EU ambassador to Russia, Markus Ederer, and handed him a note of protest.

“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,” it said. The EU diplomats must leave Russia as soon as possible, the ministry added.