An Algerian suspected of having links to al-Qaeda was being questioned by police in Northern Ireland, officials said yesterday.
"A man is being questioned about serious crime and about possessing information likely to be of use to terrorists," a spokesman for the Police Service of Northern Ireland said.
Security sources said the suspect was arrested on Monday at Maghaberry Prison in Co Antrim, where he was being held over immigration offences. Earlier, security sources had reported that the arrest took place in Belfast.
The suspect has been taken to Gough Barracks in Armagh city for questioning. Police have been given an extra 72 hours to question him.
The sources played down the suggestion of any link between the suspect and paramilitary organisations in the British-ruled province. The arrest is understood to be the first in Northern Ireland connected with al-Qaeda, which Washington blames for the September 11th, 2001 attacks on US cities and other "terrorist" attacks.
The PSNI Chief Constable, Mr Hugh Orde, said the arrest showed that "we continue to monitor all terrorism in Northern Ireland, including terrorism from international organisations".