The Department of Foreign Affairs is checking reports that an Irish man has been arrested by Syrian Democratic Forces (SDF) fighting ISIS in eastern Syria.
The Kurdish-led SDF has issued a statement claiming it has arrested five men - including one from Ireland, two from America and two from Pakistan.
It says the group was seized during an operation targeting Islamic State's last pocket of control in Northern Syria.
The Irish passport-holder is a 45-year-old man who previously lived and worked as a security guard in Dublin. He is believed to have left Ireland for the Middle East with his family in 2013.
The SDF say the arrests were made on December 30 during an operation targeting Islamic State's last pocket of control in Northern Syria. It said it had broken up a terrorist cell which was preparing to attack civilians who were trying to flee the war zone in masses.
The Department of Foreign affairs is checking the reports and the identity of the passport holder, while the Gardaí are monitoring developments.
In its statement, the SDF said: "The operation Jazeera Storm, carried out with the aim of liberating the last regions under the occupation of ISIS, continues steadily towards clearing the last bastions of the group.
"ISIS, which is now cornered in a small area after being cleared from large swathes of territory it once held, is suffering heavy losses due to operations of our forces.
"Recently, in order to prevent the advance of our forces, terrorists have attempted to carry out attacks several times.
"In this context, a group of terrorists who had been preparing to attack the civilians who were trying to get out of the war zone in masses was detected.
"Following long-term technical and physical follow-up, an operation against the cell was carried out by our forces.
"As a result of the operation, five terrorists originally from the United States, Ireland and Pakistan were captured."