The Taoiseach has said that there was no evidence linking people in Ireland with the attack on the World Trade Centre.
Bertie Ahern confirmed, however, that Gardaí have been monitoring a number of individuals, particularly over the past four weeks, who may have links with some of those involved.
He said that he would inform the Dáil if there was evidence of "anything more sinister".
Meanwhile, Gardaí are still questioning four men who were arrested as part of an investigation into the activities of international terrorist groups.
The four, three Libyans and an Algerian, are suspected by detectives of involvement in a support network connected to Osama bin Laden's Al Qaeda network.
They were arrested during raids at five addresses in Tallaght, Ballinteer and Rathmines. The four are aged 39, 31, 26 and 24.
One of those detained is a naturalised Irish citizen who is married with children. Documents and £10,000 in cash were also seized. Another man is related to a suspect for the attempted attack in Los Angeles over the millennium.
Detectives from the Middle Eastern Section of the Special Detective Unit raided the men's homes in Dublin this morning. The four are being detained under Section 30 of the Offences Against the State Act at Terenure and Kevin Street Garda Stations.
