The Department of Foreign Affairs is examining reports that a forged Irish passport may have been used by a member of an alleged Russian spy ring.
The FBI arrested 10 people at the weekend accused of carrying out deep-cover work in the United States to recruit political sources and gather information for the Russian government.
The department said one of those arrested is alleged to have travelled on a forged Irish passport, and that it would be seeking further information.
A statement issued by the department said "the firm position of the Government in regard to the fraudulent use of Irish passports is a matter of public record".
Earlier this month, the Government expelled an official at the Israeli embassy in Dublin in protest over the use of forged Irish passports by suspects in the killing of a Hamas official in Dubai.
The suspects in the alleged US-Russia spy ring were arrested on Sunday in Boston, New York, New Jersey and Virginia on charges including conspiracy to act as unlawful agents of the Russian Federation and money laundering.
Russian prime minister Vladimir Putin criticised the US arrests and said today he hoped the scandal would not set back improving Russian-US ties.
"Back at your home, the police went out of control (and) are throwing people in jail," Mr Putin told former US president Bill Clinton. "I hope that all the positive gains that have been achieved in our relationship will not be damaged by the recent event," he added.
The ten people arrested allegedly spied for Russia for up to a decade - posing as civilians while trying to infiltrate US policymaking circles and learn about weapons, diplomatic strategy and political developments.
A man suspected of being the 11th member of the spy ring has been arrested and released on bail in Cyprus, police confirmed this afternoon.
Robert Christopher Metsos (55) was arrested at Cyprus's Larnaca airport as he tried to leave the island for Budapest early today, police said.
A magistrate released Mr Metsos on bail of €20,000 bail to reappear in court within 30 days, when an extradition hearing will start.
It is not known how successful the agents had been. Among them were four couples living in suburbs of New York, Washington and Boston. One woman was a reporter and editor for a prominent Spanish-language newspaper in New York.
These alleged agents are dubbed "illegals" in the intelligence world because they take civilian jobs with no visible connection to a foreign government, rather than operating from government jobs inside embassies and military missions.
The FBI said it intercepted a message from Moscow Center, headquarters of Russia's intelligence service, the SVR, to two of the defendants describing their main mission as "to search and develop ties in policymaking circles in US."
The intercepted messages allegedly show the suspects were asked to learn about a wide range of topics, including nuclear weapons, US arms control positions, Iran, White House rumours, CIA leadership turnover, the last presidential election, Congress and the political parties.
The arrests follow a long FBI investigation.
According to the court papers, the alleged agents used invisible ink, stayed in touch with Moscow Center through coded bursts of data sent by a radio transmitter, used innocent-looking "brush" encounters to pass messages in public, hid encrypted data in public images and relied on fake identities and false travel documents.
On Saturday, an undercover FBI agent in New York and another in Washington, both posing as Russian agents, met with two of the defendants. The FBI undercover agents gave each an espionage-related delivery to make.
The court papers cited numerous communications intercepted by the FBI that spelled out what information was sought.
The timing of the arrests was notable given the efforts by president Barack Obama and president Dmitry Medvedev to "reset" US-Russia relations. The two leaders met last week at the White House after Mr Medvedev visited high-tech firms in California's Silicon Valley, and both attended the G-8, G-20 meetings over the weekend in Canada.
Fine Gael Foreign Affairs Spokesman Billy Timmins called on Minister for Foreign Affairs Micheál Martin to make contact with the Russian and US Ambassadors to Ireland to determine the background to reports of forged Irish passports being used.
“This highlights once again the vulnerability of Irish passports. It’s only five months since we learned that eight Irish passports were used by a Mossad unit which carried out the assassination of Hamas leader Mahmoud al Mabhouh in a Dubai hotel last January.
