Jane's Intelligence Review's May issue this year, three months before the arrest of the three Irish men in Colombia, reported that the guerrilla group FARC, the Basque separatists ETA and the IRA appeared to have been engaged in a technology exchange about the development of heavy mortars.
The same type of heavy weapon, based on the ordinary domestic gas cylinder, has also turned up in Iran, Sri Lanka, El Salvador and the Middle East.
Senior security sources in the Republic endorsed this opinion at the weekend and said this had been known for several years.
They claim the IRA has been specifically instructing FARC in the development of the Mark 15, or barrack-buster, 320mm mortar since 1998.
The same sources say the IRA has also been engaged in technology exchange with the Lebanese guerrilla group, Islamic Resistance, the military wing of the Muslim Hizbullah party led by Sheikh Nazrallah.
The article in Jane's, entitled "Improvised mortar systems: an evolving political weapon", was written by Mr Roger Davies, a former British army bomb-disposal and ammunition technical officer. Mr Davies examines the use and development of mortars by guerrilla and terrorist groups across the world from Sri Lanka to South America.
He points out that parallel with the IRA's development of the heavy mortar, referred to as a "flying car-bomb", the same type of weapon was being developed by guerrillas in El Salvador. Since 1998 the weapon has been most frequently used by FARC in Colombia.
Between 1998 and 1999 an estimated 10,000 heavy mortars were fired by FARC in over 100 locations. Some 84 civilians, including 12 children, were killed in these attacks, which led to the destruction of 55 police stations and 10 churches.
"While the mortars are effective in terms of their explosive quantity, they remain area weapons and as such have caused devastation of the buildings surrounding the target, usually the police station, typically located in the town square," says Mr Davies.
He adds that attacks using these gas cylinders have continued despite a senior FARC commander, Mr Jorge Briceno, admitting in an interview with a Spanish television station that they were likely to continue to cause civilian casualties.
This is the same man whose recorded conversation with another FARC figure about the three "monos" or "lads" from the IRA was reported in Colombian newspapers after the arrests.
Mr Davies describes the developing use of the gas cylinder mortars, saying: "Based on gas cylinders, the system uncannily resembles the PIRA (Provisional IRA) Mk 15 system, and there is continued speculation of technology transfer between PIRA and FARC, perhaps unwittingly via others.
"However, Colombian sources indicate that the genesis of the design can be found in similar devices used by the Farabundo Marti National Liberation Front (FMLN) in El Salvador in the early 1990s.
"Most recently unconfirmed reports indicate that ETA have produced, but not yet used, a mortar system very similar to the PIRA Mk 15 with two impact fuses mounted on the nose. Thus it would appear the idea has spread form Central American to Ulster, Colombia and Spain."
He points out that the Colombian military recently discovered the right-wing guerrilla group, United Self Defence Forces of Colombia (Auto defensas de Colombia or AUC), has also begun manufacturing the cylinder mortars.
He does not speculate about links between the IRA and Hizbullah but points out that Mujahadeen groups as far away as Iran have also been using the weapon. Hizbullah has close links with other Mujahadeen groups throughout the Middle East and south-west Asia.
He also points out that there are distinct similarities between the use of the weapon by FARC and the Sri Lanka guerrilla group, the Liberation Tigers of Tamil Eelam (LTTE). Another near-identical weapon was designed and built by Iranian Ministry of Intelligence and Security (MOIS).
"The development of these large-calibre improvised mortar systems appears to be driven by two distinct operational requirements. In the case of the LTTE (in Sri Lanka) and FARC the mortars are used as indirect fire weapons designed to bring down a very heavy weight of fire in a short time in order to disorientate and demoralise defending forces and render them susceptible to a subsequent infantry assault," he comments.
"The PIRA and MOIS systems are used as static base attack weapons designed to cause maximum casualties without a subsequent assault."
Mr Davies says the IRA's Mark 15 replaced the previous system, known as the Mark 10, best known for its use in the IRA attack on 10 Downing Street in 1991 during the height of the Gulf War.
"This (the Mk 15) remains the standard PIRA large calibre system and has been adopted and adapted by the Real IRA (RIRA) in their continuing campaign of terror. This system, believed to carry between 80 and 100kg of home-made explosive has the effect of a flying carbomb and has a calibre of 320mm. Again multiple tubes are possible with a 12-tube attack from a vehicle on a military base in Kilkeel, Northern Ireland, being a record," he says.
"JIR understands that RIRA have developed their own fusing system from the type used by PIRA. RIRA have attempted to use these mortars on several occasion over the last few months but with limited success. Most recently a mortar was abandoned on 12/13 April in County Tyrone.
"In terms of quantities and frequency of use of devices of this size, FARC guerrillas remain unmatched. Like the PIRA system the basic mortar tube is constructed from a 4ft high propane gas cylinder, the bomb containing up to 100kg of home-made explosive.
"In the late 1990s FARC started deploying large-calibre mortars in support of their conventional insurgent attacks against security force bases, often in substantial quantities. The Colombian army claims that 10,000 such devices were used against targets in over 100 locations in 1998-99."
Senior security sources here indicate that while the IRA has been pursuing relations with foreign terrorist groups, particularly ETA and FARC, there is no impression that it is intending to resume its terror campaign in Northern Ireland and Britain, at least in the short term.
Instead, it is felt the IRA is using this "technology exchange" to continue improving its own skills and to acquire funds and/or arms.
It is thought the relationship with FARC is financially driven, as FARC is extremely wealthy from its involvement in the cocaine and heroin trade.