A 28-year-old American military veteran has joined the civilian fight against the Islamic State (IS) in order to help the persecuted Christians in Iraq and Syria. 

The man, known only as Brett, joined the Dwekh Nawsha Christian militia and is stationed in Al-Qosh in northern Iraq, according to the Daily Mail. 

The ancient city was home to a large Christian population, but many have fled to Kurdistan because of IS violence. Brett said that the religious minorities are still worth fighting for. 

"One man's terrorist is another man's freedom fighter," he said from Dohuk, Kurdistan.

"But here we're actually fighting for the freedom of the people here to be able to live peaceably, to be able to live without persecution, to keep the church bells ringing."

Thousands have been killed and millions displaced by the terrorists, who seek to establish a militant Sunni Muslim regime across the targeted countries.

Brett is recruiting foreign fighters to help the countereffort, and has already identified five volunteers from Canada, Britain, and the US. 

The first recruit was Louis Park, a former Marine from Texas. Diagnosed with post-traumatic stress disorder and "some other things," Park retired in December and is unable to return to military combat. The Dwekh Nawsha Christian militia became his opportunity. 

"I did not adjust well at peace time," Park admitted. "I wanted to get back out here... I'm patriotic as hell. If my government won't fight them I will."

The Daily Mail reported that the militia has only a few hundred fighters at present.