A 22-year-old Briton who enlisted with a Kurdish militia has been killed fighting in Syria against Islamic State, his father said.

"My son Dean Carl Evans born 7/10/93 was killed in Syria on Friday, he was loved and will be missed by all his family and friends rip son," said John Evans in a posting on Facebook.

"I would like to say a massive big thank you to all my freinds and family who sent there condolence for the loss of my son he would have been very proud and would have regarded you all as his brothers and sisters,thank you again," he posted.

The International Brigades of Rojava of the Kurdish YPG, or People's Protection Units, announced Evans's death on social media. It said the Briton had been "martyred" in an operation against Isis on 21 July in Manbij, northern Syria.

It said a Slovenian volunteer named as Martin Gruden had also been killed.

A tribute to Evans has been posted on YouTube by a YPG linked account.

In recent days US-backed forces are believed to have seized control of up to 70 per cent of the strategically vital town near the Turkish border in clashes with Isis militants.

In March, former Royal Marine Konstandinos Erik Scurfield became the first Briton to die fighting with the YPG against IS.