It is believed the IRA sent a unit from its bomb and mortar-making section to co-operate with the Colombian narco-terrorist group, FARC (Revolutionary Armed Forces of Colombia) as part of a system of "technology exchange" under the auspices of an international terrorist network.
One of the men is from Armagh, one from Donegal and the third man is resident in Cuba and may have been an interpreter. He is believed to be Niall Connolly (34), originally from Blackrock, Co Dublin.
One of the three is Martin McCauley (37), who was shot and seriously injured by the RUC during an incident at a barn outside Lurgan, Co Armagh, in November 1982. His companion, Michael Tighe (17), was shot dead.
The second man is James Monaghan described by the Colombian authorities as the leader of the group. He was named in the Northern Ireland Assembly as a senior IRA figure in a speech by the DUP deputy leader, Mr Peter Robinson, last May.
The IRA's main interest in groups like FARC is reportedly to acquire new technical expertise and, in turn, to share some of its experience.
According to senior security sources in Belfast, the IRA operation in Colombia was directed by a senior IRA figure from Belfast. This man also has responsibility for the IRA's contact and deliberations with Gen de Chastelain's Independent International Commission on Decommissioning (IICD).
The links between the IRA and foreign terrorist groups is well known and is monitored by the RUC and Garda with the help of foreign police forces and intelligence agencies.
A number of important Provisional IRA figures have established links with and, in some cases, are living in Latin American countries and have made contacts with other terrorist groups. One of the men sought by gardai in connection with the murder of Det Garda Jerry McCabe in May 1996 is living in Central America.
The IRA's links to FARC could go back four or five years, or even more. FARC has carried out about 112 bomb attacks in Colombia this year, many of them similar to IRA at tacks during its campaign.
There have been suspicions for a long time that the IRA has been sharing its expertise. Devices strikingly like one of its Mark 15, or "barrack buster" mortars, have turned up in several countries, giving rise to suspicion that the IRA has been selling its techniques abroad.
A small core of IRA figures travels widely and keeps contact with revolutionary terrorist groups. It is believed the contact with FARC came through the IRA's close links to the Basque separatists ETA. ETA and FARC share a common language and have helped each other in the past.
It emerged in 1999 that ETA and the IRA were involved in joint activities in Latin America. Information from statements taken in the case against four Irish people caught smuggling guns from Florida indicated that the IRA man who was in charge of the operation - but who was not charged - had links to ETA.
Information also reached the FBI that the IRA had a stockpile of arms in Panama ready for shipment to Ireland. An American man who was involved in the IRA arms smuggling plot in 1999 was known to have previously been involved in drug smuggling from Colombia.
It is likely that the IRA would develop links with a group such as FARC which shares some of its revolutionary attitudes and which is also cash-rich through its activities as a drugs cartel.
FARC has an estimated 17,000 uniformed soldiers and 5,000 part-time urban militia members. It funds its war against the Colombian government through the drug trade, kidnapping civilians for ransom and taxing businesses in areas it controls.
According to Alfredo Rangel, a Colombian military analyst, profits from the drug trade now make up 48 per cent of FARC's income, amounting to an estimated $180 million annually.
FARC initially opposed involvement in the drugs trade. But, as the trade became more lucrative, FARC began levying a 10 per cent tax on fields of coca and opium poppies, the raw materials for cocaine and heroin, and collecting fees for every narcotics flight leaving rebel-controlled zones.
After the break-up of the Medellin and Cali drug rings in the early 1990s, FARC's involvement in the narcotics trade grew. They also provide military support for the "mini-cartels" that sprang up and often turned to the rebels for protection.
The US regards FARC as one of the most serious problems in Latin America. Last year, Congress approved a $1.3 billion package of mostly military aid to help the Bogota government combat drug traffickers. Much of the assistance is being used to target the rebels. FARC has kidnapped some 120 US citizens in the past 20 years, killing at least 14. Three Americans were murdered in March 1999.
The US Department of State, on its website, warns American citizens against travelling to Colombia, citing violence by "narco-traffickers, guerrillas and other criminal elements".
The State Department says: "Most kidnappings of US citizens in Colombia have been committed by guerrilla groups, including the Revolutionary Armed Forces of Colombia (FARC) and the National Liberation Army (ELN), which were both designated as foreign terrorist organisations by the Secretary of State in October 1997.
"Since it is US policy not to pay ransom or make other concessions to terrorists, the US government's ability to assist kidnapped US citizens is limited."
Gen Fernando Tapias, Colombia's armed forces commander, describing the arrests of the three men, said: "This capture is more proof of the ties between FARC and various international extremist groups of different countries, with the intention of increasing its capacity to commit terrorism and the traffic in arms and narcotics."