The Department of Foreign Affairs has been asked to intervene in the case of a Belfast freelance journalist who was arrested by the Israeli authorities in the West Bank at the weekend.
According to Ciarán Ó'Pronntaigh, editor of the Irish language newspaper Lá, the arrested man - Seán Ó'Muireagáin – is totally innocent.
Mr Ó'Muireagáin, 40, is being questioned about possible links between Irish terrorists and Palestinian militants.
Mr Ó'Pronntaigh called on the Israeli authorities to release him immediately.
The Belfast office of the Ireland Palestine Solidarity Campaign Mr Ó'Muireagáin is a peace activist who had no terrorist connections.
A member of the solidarity group, Caithlín Connell, said Mr Ó'Muireagáin was visiting the region in order to improve his understanding of events in the Middle East conflict, and that the Israelis had made a mistake.
A spokeswoman for the Israeli Foreign Ministry said the government would not respond to claims of mistaken identity for security reasons.