The US is pulling out all of its troops from northern Syria as Turkey advances its operation against the Kurds.

Defence Secretary Mark Esper said Turkey “likely intends” to extend its attack further than originally planned.

The assault is aimed at forcing out Kurdish forces – the main US ally in the area. They may be seeking help from Syria and Russia, said Mr Esper, and the US would not be defending them.

Syria has now announced it is sending troops north to face Turkish forces.

More than 130,000 people have fled homes near the conflict, the UN said, warning the figure could soon triple.