Minister of State Liz O'Donnell has extended the sympathy of Ireland to the families of victims of the World Trade Centre bombings.
"It's very chaotic with a lot of phone lines jammed, so we don't yet have details on Irish casualties, if any. We are advising Irish people in the United States to phone home to reassure relatives who may be worried about them."
She added that the Department of Foreign Affairs was keeping in touch with Irish Missions in the US.
Taoiseach Bertie Ahern earlier called for "global solidarity" in the face of terrorism.
Foreign Affairs Minster Brian Cowen, who had been on a fact-finding mission to the Middle East, is cutting his visit short and will fly home from Tel Aviv tonight.