BEIRUT: An Australian citizen fighting with Syrian rebels in their battle against President Bashar Assad’s regime has been killed in the northwest of the country, an opposition-aligned watchdog said Wednesday.

“Abu al-Walid al-Australi was killed Dec. 30 in a rebel assault on the Wadi Deif base,” Rami Abdelrahman, director of the Britain-based Syrian Observatory for Human Rights, told AFP by telephone.

Rebel fighters launched an assault on the Wadi Deif base, one of the regime’s last strongholds in the northwest of Syria, on Dec. 28 in a fresh bid to wrest control of the strategic post.

The jihadist group the Nusra Front led the offensive, according to rebels on the ground.

Insurgents captured the nearby town of Maaret al-Numan, located on the important Damascus-Aleppo highway, in October.

Syria’s insurgents comprise army deserters, civilians who have taken up arms and foreign fighters, including several Islamist groups.

The Australian newspaper reported the man is believed to be Melbourne-based Turkish-Australian Yusuf Toprakkaya.

A Department of Foreign Affairs and Trade spokesperson told the newspaper it was not able to confirm the reports but was making inquiries.

The Australian government has condemned Assad’s regime for its violence against its own people, expelled Syrian diplomats and demanded the president’s departure.