“He thought this was such an important fight and he has always been a man of principle, who believed very strongly in human rights and justice,” she wrote. “I am very, very proud of him and his sisters and I love him very much.”

The Facebook profile listed Gallagher as born in Wheatley, Ont., and residing in Calgary.

Members of the Canadian Armed Forces who previously served with Gallagher told CTV’s Mercedes Stephenson that he was intelligent, principled, noble and a good soldier.

They also said he believed strongly in the fight against ISIS, and that Western countries weren’t doing enough.

The Syrian Observatory for Human Rights, an activist group, issued a press release Wednesday that said an unnamed Canadian was killed when an ISIS fighter detonated an explosive belt on a farm around the village of Dalho, in the El-Hol area, east of al-Hasakah City in Syria.

After the Gallagher family was informed of the death, SOHR issued another press release confirming his identity.

Fighters on the ground told CTV News Gallagher had travelled to Syria in mid-2015 and was the only victim of the suicide bombing, although two others were injured.

The People’s Defense Units (YPG) says they are now in possession of his belongings and passport.

Other Canadians are currently fighting in the area, but they were not present at the blast site.

The Syrian Democratic Forces include fighters from the Jaysh al- Thuwar, Borkan al- Furat Operation Room, Jaysh al- Sanadid and the Brigade Groups of al- Jazira, the Syriac Military Council, the People’s Defense Units (YPG), the Women’s Defense Units (YPJ), according to SOHR.

The forces have been involved in ongoing fighting against ISIS in the al-Hasakah City area.