Ireland is "not neutral" when it comes to assassinations or the use of chemical weapons, Taoiseach Leo Varadkar said yesterday as a Russian diplomat was chosen for expulsion.
The country is now embroiled in growing tensions reminiscent of the Cold War, sparked by the attempted assassination of a former spy in England earlier this month.
Russian president Vladi- mir Putin has been briefed on the decision of the Irish Government to join more than 20 countries in expelling diplomats.
His ambassador to Ireland, Yury Filatov, was summoned yesterday to a brief and frank meeting at the Department of Foreign Affairs, where he was told the name of a diplomat whose accreditation is to be terminated.
The Herald understands the diplomat in question is considered "mid-rank" and will leave in the coming days.
He was not chosen at random, but on the back of ongoing work by gardai.
Mr Filatov described the expulsion as "totally unwarranted, uncalled for, senseless and regrettable".
He claimed the world is witnessing a "complete cover-up" of the poisoning of Sergei Skripal in Salisbury.
Asked whether retaliation from Moscow is likely, the ambassador said the Government's decision "would not go unanswered".
More than 20 countries have expelled diplomats, including Finland and Sweden, which are also considered neutral.
Mr Putin is expected to formally announce his response later this week, though sources say it is not certain he will enter a tit-for-tat with smaller countries such as Ireland.
Mr Filatov said his colleagues at the Russian embassy in south Dublin have "done nothing illegal".
Speaking in the Dail, Mr Varadkar defended himself against accusations that he had gone into "full macho mode" by joining forces with French president Emmanuel Macron to convince EU leaders to take action.
He added that Ireland's long-standing neutrality is not under threat.
"We do not join military alliances, we will not be joining NATO and we will not be part of a European army. However, when it comes to terrorism, assassinations, the use of chemical weapons and cyberterrorism, we are not neutral one bit," he said.
After initially expressing reservations, Fianna Fail last night backed the move.