The Department of Foreign Affairs has said that one of the people arrested in the US on suspicion of being a spy is alleged to have travelled on a forged Irish passport.
Ten suspects were arrested on Sunday across several states for allegedly serving for years as secret agents of Russia's intellegence organistion the SVR.
One person is believed to still be on the run.
Russia's foreign minister says he wants an explanation from the US on the matter.
The Department of Foreign Affairs here says it will seek further information on the reports and that the firm position of the Government in regard to the fraudulent use of Irish passports is a matter of public record.