RTE is reporting that a former member of the Defence Forces has been detained in Syria over alleged membership of ISIS.
According to reports, the Defence Forces member is a woman who had left the forces around five years ago.
It is understood that the woman, who had held the rank of private, was subsequently radicalised before leaving Ireland in 2016.
The Department of Foreign Affairs said it was aware of reports of an Irish citizen detained in northern Syria, but did not confirm them.
It is understood that she is travelling on an Irish passport and she has a young child.