Garda sources have confirmed that a man who has been named as having been captured in Syria by militias fighting against ISIS is an Irish citizen.
The man, who is 45 years of age and originally from Belarus, is the holder of an Irish passport.
He lived and worked in this country for a number of years.
In 2013, he left with his family to go to the Middle East.
Gardaí say the man was known to them in the context of the monitoring of individuals sympathetic to radical causes.
A spokesperson for the Department of Foreign Affairs has said no requests for consular assistance on behalf of an Irish citizen captured in Syria have been made to it.
Speaking in Mali, Taoiseach Leo Varadkar said he was aware of the situation, but could not comment further as he did not know the full details in relation to it.
However he also said that any Irish citizen around the world is entitled to consular assistance and will get that.
He said: "I've only heard about that in the last short while. The information we have is that an Irish citizen has been taken into custody in Syria. We don't know the details of that so I can't comment on it in any detail but what I can say is that any Irish citizen around the world is entitled to consular assistance and will get that."