Colombian military authorities were last night still detaining three men who they said were suspected of travelling on false passports and making contact with guerrilla groups in the country.
Garda sources said last night they were investigating links between the arrests and activities by the Provisional IRA in South America.
Colombian police contacted the Garda and the RUC on Sunday seeking information about the men. It is understood the identities of two were established yesterday. They are from the Republic. The identity of the third was still being established last evening, but it is also believed he may be from the Republic.
The Colombian authorities said two of the men were travelling on false British passports. This had been established through contacts with the RUC. The third was travelling on an Irish passport, also said by the authorities to carry a false identity.
Aside from the Colombian authorities reporting that the three were travelling on false passports there was no suggestion of any evidence that they were involved in any illegal activity.
It is understood the three were arrested when they arrived at Bogota Airport after travelling to a demilitarised area in south-eastern Colombia that the government ceded to the Revolutionary Armed Forces of Colombia, Colombia's largest guerrilla group, 2 1/2 years ago.
Tight security still surrounds the area. The civil war in Colombia involving leftist rebels against the army and outlawed right-wing paramilitary groups has left 40,000 civilian casualties in the last decade. Peace talks have failed to bring an end to the war.
The Sinn Fein leader, Mr Gerry Adams, is due to visit South America later this month as part of a three-week lecture tour. There are links between Sinn Fein and left-wing and revolutionary groups throughout the Third World.
Mr Adams has regularly spoken at left-wing gatherings in Europe. Colombian left-wing guerrillas and their political wings have long-established links with the Basque separatists in ETA and its political wing, Herri Batasuna, and Sinn Fein has had close links with the Basques for over two decades.
More details of the arrests were due to be released at a news conference by the military authorities in Bogota at 3.30 p.m. local time.
The Press Association's Belfast office, quoting RUC sources, said last night forensic tests for traces of explosives were carried out on the three men's clothes. There was no suggestion that the tests had shown they had had any contact with explosives or firearms or were involved in any conspiracy to smuggle explosives.
The deputy leader of the DUP, Mr Peter Robinson MP, said he had been alerted by UK intelligence of the arrests and claimed they could have implications for Gen John de Chastelain's decommissioning body.