Three Irishmen are still in custody in Colombia today accused of travelling on false passports. Garda sources believe the three were there on IRA activity.
It has been alleged they were training local FARC rebels in explosives and terrorist tactics.
Two of the arrested men were identified by officials in Colombia as Mr Martin McCauley and Mr James Monaghan, residents of Northern Ireland. The third man was travelling under the name David Bracken, which is believed to be false.
Asked about the affair at a news conference in Belfast Sinn Féin's Mr Mitchel McLaughlin hinted that they were republicans.
"Yes, some of them certainly are, and they would be known to the media."
Earlier, he had urged caution, saying, "The information is very scant. People have been arrested, nobody has been charged, nobody has signed confessions."
He also warned of "a propaganda dimension" in the way information about the arrests had emerged.
Colombian officials claimed forensic tests on the clothing of the three turned up traces of four kinds of explosives and of cocaine, it was reported.
Colombian Defence Minister Mr Gustavo Bell told a news conference the three were arrested in Bogota on Saturday after spending five weeks training members of the Revolutionary Armed Forces of Colombia - FARC - in a rebel safe haven in southern Colombia.
It was reported the three were captured after getting off a flight from San Vicente del Caguan, the largest town in the demilitarised zone ceded to the FARC by Colombian President Mr Andres Pastrana in 1998. They were said to be intent on boarding a plane bound for Paris.
Officials showed a video of the three shortly after their arrest - in which they did not speak - and claimed they had entered Colombia with false passports at the end of June.
UK security sources said the Colombian authorities had been in contact with the RUC about the three IRA suspects, exchanging fingerprint tests and photographs.
PA, AFP