The Government warned Russia last night that there could be no justification for a threatened retaliation over the expulsion of a diplomat from their embassy in Dublin.
The warning salvo was fired after Russian deputy foreign minister Vladimir Titov described the expulsion as a "groundless and unfriendly act" and said it would not take place without a corresponding reaction.
The Russian diplomat is being thrown out of Ireland after a garda investigation concluded that members of the Russian intelligence service, the SVR, were involved in the forgery of Irish passports held by spies arrested in the US last summer.
Senior Irish sources said privately last night they were not aware of any plans by the Russian authorities to expel any official serving with the Irish Embassy in Moscow.
They said there was no reason why an Irish diplomat should be expelled and that any such move would be merely a face-saving exercise.
Mr Titov's intervention in the passport controversy was reported by the Interfax news agency in Moscow.
However, it is understood that no corroborative evidence of a tit-for-tat strike by the Russians has yet emerged.
A government spokesman said last night they were not aware of any threats of retaliation and pointed out there would be no justification for expelling an Irish diplomat.
Staff at the embassy in Moscow had no intelligence functions of any kind and retaliatory action would be unwarranted, he added.
The spokesman said: "It is well understood internationally that Ireland does not engage in espionage activity or passport forgery. Any retaliatory action against Irish diplomats would be seen as being entirely without foundation. Our action yesterday was to address a serious problem which had arisen.
"Now that this matter has been dealt with, we hope we can move on and develop the very good relationship which exists between Ireland and Russia on so many other levels."
The Department of Foreign Affairs recommended the Russian diplomat be expelled after studying the garda report and this was approved by the Government at Tuesday's cabinet meeting.
Ambassador Mikhail Timoshkin was then told by department secretary general David Cooney that accreditation for a named official at their embassy in Rathgar, Dublin, was being withdrawn.
The man must leave the country within a fortnight.
Six passports belonging to innocent Irish citizens were compromised by the Russian action, which involved replicating the details of the passports on fake documents.
The forged passports were then passed on to members of a Russian spy ring, who had been operating undercover in the US until the network was broken up last June by the FBI.