A former Australian politician was on Sunday arrested at Darwin Airport after returning to the country from Middle East where he allegedly helped Kurdish fighters against Islamic State (IS) militants.
Matthew Gardiner, the former Northern Territory Labor party president who had left Australia in January, was stopped by customs officials at the airport after flying from the Middle East via Sweden and Singapore, Sydney Morning Herald reported.
Gardiner, 43, made connections with people on social media who were sympathetic to the Kurdish cause.
He could travel to Syria at that time because he was not on any Federal Police watch lists at the time.
The Kurds have been involved in a bitter battle with Islamic State since the jihadist group invaded their territory last year.
The Australian Federal Police (AFP) confirmed they spoke to a Darwin man who returned to Australia this morning.
An AFP spokesperson said enquiries relating to the man's activities while overseas were ongoing and they would be providing no further comment.
Gardiner, 43, previously served as an Australian Army combat engineer in Somalia in the early 1990s.
He was stood down as president of the party and had his membership suspended after leaving, according to a statement from Territory Labor.
A spokesperson for Attorney-General George Brandis said it was not appropriate to comment on Gardiner's return as it was now a law enforcement matter.
The Attorney-General's department has long maintained that Australians who leave Australia to engage in an illegal conflict and then come back, will be arrested, prosecuted and jailed.
Under the current legislation it is possible for Australians to join the armed forces of a foreign country.
However, the Kurds are not recognised as a legitimate armed force. There are an estimated 100 westerners currently fighting with Kurdish forces.
In February, fellow Australian 28-year-old army reservist Ashley Johnston was killed on the frontline in Syria fighting with Kurdish forces against Islamic State militants.