The commander-in-chief of the Colombian army, General Fernando Tapias, told a congressional hearing yesterday that at least seven IRA operatives had been in the country, training members of the rebel army, Farc.
These include the three Irishmen - said to be the IRA's two most senior explosives experts and Sinn Fein's political representative in Cuba - who were captured last year and are awaiting trial in Colombia.
The general gave the names under which the other four were travelling as John Francis Johnston and John Edward Walker, who visited Colombia briefly last April, and Kevin Noel Creenle and a woman with an Icelandic name Margaret Osk Steinsdorddottir, who were both arrested but released for lack of evidence.
General Tapias said the IRA was providing know-how and technical assistance in arms production and that Farc's terrorist methods had changed since the Irish connection became established.
However, he admitted that he had no evidence to show the IRA had sent any of these people to Colombia or was even aware of their presence. Indeed, most of the evidence suggested that the house of representatives international committee, which called the hearing, knew much less about the IRA's presumed activities than its advance publicity suggested.
Gerry Adams, the Sinn Fein president who announced on Tuesday that he would not give evidence, would probably have had an easier ride than he might have feared. Several members, of both parties, denounced the committee's own investigation, which hinted enticingly at a proven link between the IRA and the international drugs trade.
The Massachusetts Democrat, William Delahunt, said: "We have been presented with a report short on facts and replete with speculation, surmise and opinion." The New York Republican, Peter King - a Sinn Fein sympathiser - said there was no evidence linking the IRA to drugs trafficking in the Western hemisphere and warned that the innuendo was damaging the peace process.
The committee chairman, Henry Hyde, has some history of promising more evidence than can be delivered - he led the impeachment of Bill Clinton. "What are members of the IRA doing in Colombia?," he asked. "Claims that these individuals were there for benign purposes - specifically eco-tourism or activities related to the Irish and Colombian peace processes - are an insult to our intelligence." The report, issued by the committee's investigative staff after a nine-month study, said the links between the IRA and Colombian narco-terrorists date back to at least 1998.
It added: "In the light of the long history of strict IRA discipline against freelancing by its membership, the only real question remaining in the committee's inquiry concerns what the Sinn Fein leadership knew about these IRA activities in Colombia, and when did they learn of them." Earlier, the IRA firmly denied any involvement, past or present, in Colombia.
A statement from the pseudonymous P O'Neill said the Provisionals felt compelled to reiterate what they said last September because of the way republicans felt the arrest of the three Irishmen in Colombia had been used to undermine the peace process.
"The [IRA] army council sent no one to Colombia to train or engage in any military co-operation with any group," the statement continued.
The Ulster Unionist leader, David Trimble, is so far adopting a measured approach, but he will come under increased pressure from hardliners to impose sanctions on Sinn Fein's participation in the power-sharing Stormont government.