Two diplomats have been asked to leave the Irish Embassy in Moscow, according to the Department of Foreign Affairs.
In a statement, the Minister for Foreign Affairs Simon Coveney said: "The Ambassador of Ireland to the Russian Federation was summoned to the Foreign Ministry in Moscow this afternoon and informed that two diplomats from our Embassy in Moscow have been asked to leave."
He added: "There is no justification for the taking of this measure.
"The staff at the Embassy of Ireland in Moscow do not have, nor are engaged in, any duties or functions which are incompatible with their diplomatic status.
"This decision to reduce the size of our relatively small Embassy in Moscow will significantly reduce our ability to provide services to our citizens in Russia and to maintain diplomatic channels of communication with the Russian Federation."
The Russian Embassy in Ireland said Irish ambassador Brian McElduff had been called in to listen to its protests over what it called "groundless steps" taken by the Irish authorities last month "who demanded the departure of four employees from the country".
In March, four senior officials at the Russian Embassy were asked to leave the State.
The Taoiseach has told the Dáil the move followed security advice received by the Government.
The Government said the officials' activities have not been in accordance with international standards of diplomatic behaviour.
