Sinn Féin president Gerry Adams has protested to the US authorities about his detention at a Washington airport.
Mr Adams missed a flight to New York, where he was due to attend a function at the Buffalo Irish Centre on St Patrick's Day.
He was detained along with Sinn Féin official Richard McAuley because their names were on a terror watch list.
"I am deeply disappointed that I could not attend the events in Buffalo," said Mr Adams last night.
He said he had consistently raised the problem of additional security screening with the US administration.
"While I understand the need for vigilance Sinn Fein members are the victims of an unacceptable and unfair administrative practice. We have protested again today to the Administration," he said.
Mr Adams and Mr McAuley opted for a six-hour train journey from Washington to Boston yesterday instead of the hour-and-a-half long flight