A group of foreign fighters, including three Britons, is heading to the Syrian city of Afrin to join the Kurdish YPG militia in their fight against Turkey.

The news came as Turkish President Recep Tayyip Erdogan vowed on Wednesday to press Turkey’s offensive against Kurdish militias in Syria until “the last terroristthe last terroristthe last terrorist” was killed.

The offensive was “continuing successfully”, said Erdogan, adding that Syrian opposition fighters and Turkish forces were “step by step taking control of Afrin”.

Turkey launched “Operation Olive Branch” on Saturday aiming to root out the Kurdish People’s Protection Units (YPG) militia, which it sees as a terrorist group.

The Afrin offensive has caused concern among Turkey’s Nato allies, especially the US, which continues to supports the YPG in its efforts to defeat Islamic State in Syria.

“We are all ready to go and fight in Afrin,” a spokesman for the foreign fighters said in a video posted online.

“We have been training for a significant amount of time in tactics that work against any force. We are prepared and have been supplied by the YPG to fight against Turkish terrorists,” said an unnamed spokesman, who had an American accent.