Russian-backed separatists in east Ukraine say 24 of their fighters have been killed in a rocket attack on the recently captured airport outside their main stronghold city of Donetsk.

Rebel defense spokesman Eduard Basurin said the terminal was targeted by Ukrainian government forces Friday with Uragan multiple rocket launchers.

The separatist seizure ofthe virtually obliterated airport this week after months of bitter battles was a major blow for beleaguered Ukrainian offensives in the east.

Diplomats from Russia, Ukraine, France and Germany met this week to thrash out a tentative dividing line from which the warring sides would pull back their heavy weapons.

Separatists have warned, however, that they intend to continue their advances and take more territory.