A British film-maker is understood to have been killed in Syria by Islamic State militants.
Mehmet Aksoy, 32, who grew up in England, is believed to have joined a Kurdish military force, The People's Defence Units, working as a press officer.
He was killed on Tuesday morning in a Daesh attack while he was on duty in Raqqa, according to the YPG website.
Breaking: British filmmaker Mehmet Aksoy killed in Syria by IS attack on YPG compound near Raqqa the BBC understands pic.twitter.com/EGFmBesEAv— Emma Vardy (@EmmaVardyTV) September 27, 2017
The website says Mr Aksoy was the founder and editor-in-chief of Kurdish Question, which examines the problems of the Kurdish people and other ethnic groups.
It says he completed a university education in film-making and produced pieces for cinema, literature and other fields of art, with a series of short films and poetry.
A Foreign Office spokeswoman said: "The UK has advised for some time against all travel to Syria. As all UK consular services are suspended in Syria, it is extremely difficult to confirm the whereabouts and status of British nationals in the country."
Aladdin Sinayic, a close friend of Mr Aksoy's from London, told the BBC: "Mehmet never fought, the plan was never to fight.
"He told me there are better ways. He wanted to tell the stories of the fighters there, he had so much respect for them, and Mehmet was loved by everybody."
Mr Aksoy is believed to be the fifth British citizen to die while working alongside the Kurds in Syria.
Luke Rutter, from Birkenhead, was killed in Raqqa on July 5, and former chef Ryan Lock, 20, from Chichester, West Sussex, shot himself to avoid falling captive to IS last December.
Dean Evans, 22, a dairy farmer from Reading, Berkshire, died in the city of Manbij in July last year, and former Royal Marine Konstandinos Erik Scurfield, 25, from Barnsley, South Yorkshire, died in the northern village of Tel Khuzela in March 2015.