Islamic State fighters are reported to have renewed their advance in the Syrian border town of Kobane, as the US warned air strikes alone could not save it.

A Kurdish leader inside Kobane said that IS militants had entered two districts amid heavy fighting.

Seizing Kobane would give the IS jihadists full control of a long stretch of the Syrian-Turkish border.

The US also appeared to be at odds with allies, over a Turkish idea to create a buffer zone or safe haven along the border.

400 people have died so far in the battle for the town.