Up to 25 Irish republicans could have linked up with Marxist rebels in Colombia, it has been claimed.
The claim was made by authorities in Bogota investigating three Irishmen who were arrested last August.
Mr Niall Connolly, Mr Martin McCauley and Mr James Monaghan are being held in a jail run by Columbia's judicial police force in Bogota. The three men are expected to face charges later this year.
Authorities now say that between 15 and 25 Irishmen visited the zone controlled by FARC rebels. They also believe two other republicans were in the rebel-controlled zone at the time of the arrests and may have escaped through Venezuela.
Following the claim, Ulster Unionists have demanded decisive action by the US authorities against Sinn Féin.
Northern Ireland's economy minister Sir Reg Empey said: "The issues of visas and fundraising have to be looked at. There is a clear case to answer".
PA