Fierce fighting has erupted in the north of the Syrian town of Kobane, after two days of relative calm, the BBC reports.
The clashes began when Islamic State (IS) militants launched an offensive “on all fronts” against Kurdish fighters on Monday, activists said.
Meanwhile, the US-led anti-IS coalition said it carried out six air strikes around Kobane on Sunday and Monday.
Kobane, on the Turkish border, has been been under assault from IS for weeks, with most civilians forced to leave.
The new fighting came as Turkey said it would allow Iraqi Kurdish Peshmerga fighters to cross into Syria to fight IS.
Officials in the Iraqi Kurdish region said they were ready to send forces but had so far received no orders to do so.