Ashley Johnston, who was killed fighting for the Kurds in Syria. A Defence spokeswoman confirmed the dead man was a former Army Reservist but would not confirm his name. Ms Olan said: "He was a hero. He went all the way from here to fight for humanity. We will have him in our hearts forever." The Syrian Observatory for Human Rights, which is based in London, announced on Thursday that an Australian man was killed in an IS assault against a position of the Kurdish People's Protection Units (YPG) near Tal Hamis in Hasakeh province. The YPG posted a Facebook tribute to Mr Johnston, who they called "Heval Bagok Serhed".

"We the YPG regretfully inform you of the death of one of our bravest Western fighters Heval Bagok Serhed. He is the first Western fighter to be martyred fighting the evil of ISIS. Rest in peace our brother," the Facebook group "the Lions Of Rojava" said. "Throughout his time in Kurdistan he had a positive impact on my people's lives though his humility and kindness to everyone he met. He was taken from us in a heroic assault on ISIS positions in a small village near Shingal. His squad of eight fighters were in a truck which had broken down and it was critical that they dislodge ISIS form their positions so they pushed on fearlessly with little regard for the own safety. "They where massively outnumbered and outgunned but fearless in the face of this as they knew another ISIS death meant saving the lives of countless civilians. He was a fearless and exceptional soldier as well a great man. "Please keep his family and loved ones in your prayers and remember him and his heroic actions, which saved his comrades." It is believed that Mr Johnston was with Jordan Matson, an American volunteer who has criticised the Australian government for making it a jailable offence to fight for the YPG.

Fairfax Media also spoke to a Kurdish Syrian translator, Sabry Omar, who saw the Australian, who he named only as "Ashley", on Mount Sinjar in Iraqi Kurdistan last month. "He was on the frontline when he was injured - I saw him in hospital, but he was not seriously hurt," he said. "A suicide bomber in a car exploded near him and his eyes were injured." Mr Omar last saw Ashley on some social media sites, on January 28 or 29, he said. "His nickname was Gabar - which is the name of a Kurdish mountain in Turkey. "He had many tattoos ... I am sure he must have been a professional soldier in Australia from his level of experience [as a fighter] ..."

The news of the Australian's death travelled fast through Kurdistan and the Kurdish controlled enclave of Jazira in north-eastern Syria. Mr Rahman said dozens of Westerners had joined the YPG's ranks. "There are foreigners fighting on all sides of Syria's war ... They are volunteers, they don't get paid anything at all," he said. "The YPG isn't actively recruiting foreigners, but people from countries like Canada, the United States, Britain, Spain, Australia, Holland, Austria and France have travelled to Syria to join their ranks," he said. A spokeswoman for Foreign Minister Julie Bishop said the government could not confirm the man's name.

A Department of Foreign Affairs and Trade spokeswoman said: "We are aware of reports that an Australian male has reportedly been killed in northern Syria (on Tuesday 24 Feb). "The Australian government's capacity to confirm reports of deaths in either Syria or Iraq is extremely limited. Due to the extremely dangerous security situation, consular assistance is no longer available within Syria. Australians who become involved in overseas conflicts are putting their own lives in mortal danger. Any Australians fighting with non-state militia in Syria or Iraq should end their involvement in the conflict now and leave the conflict zone. Australians are strongly advised not to travel to Syria or Iraq; any Australians in either country should leave immediately. For further information, please see www.smartraveller.gov.au ." DFAT has urged all Australians in the Middle East fighting IS to return home. In October, Attorney-General George Brandis warned that any Australian fighting for the YPG would face prosecution under the Foreign Incursions and Recruitment Act and a possible jail sentence of up to 20 years. YPG has been linked to Kurdish group PKK, which is a proscribed terrorist organisation according to the Australian government. In a message on Facebook, Jordan Matson said: "Ashley was a good man who never complained and was always positive. He came to defend his country even after his country labelled him a criminal for doing so."

A Twitter account called KurdishPhoto posted on Thursday: "Ashley from Australia. You are a freedom fighter, a martyr and will forever live in the hearts of the Kurdish people".