It is believed the man was entering Iraq from Syria
The Department of Foreign Affairs has confirmed an Irish citizen has been arrested in Iraq.
Joshua Molloy, who had been fighting against the so-called Islamic State in Syria, was arrested on Friday having allegedly entered Iraq illegally from Syria.
The Sunday Times reported the man was detained along with two British nationals in the city of Erbil, and that the men were fighting alongside Kurdish fighters in Syria.
It is understood the 24-year-old man is a former member of the British. He was arrested along with two British nationals. The UK Foreign Office confirmed that they have been in contact with local authorities and that the three men are being held.
The Department of Foreign Affairs has confirmed that it is aware of the case and that the Irish government stands ready to provide consular assistance. Minister Charlie Flanagan is being kept fully informed.