SEVEN Ukrainian soldiers have been killed after ­separatist shelling hit their armoured vehicle near Donetsk airport in eastern Ukraine, putting a fragile ceasefire under further strain.

It was the largest loss of life among Ukrainian soldiers in a single incident since the ceasefire came into force on September 5 and cast a shadow over President Petro Poroshenko's upbeat assertion last week that the worst of the war against the separatists was over.

Military spokesman Andriy Lysenko said tank fire from the separatists struck a large armoured carrier on Sunday night during rebel attempts to storm Donetsk international airport, which is held by government forces.

The rebels hold key points inside the city itself, an industrial hub with a pre-war population of about one million.

Mr Lysenko said: ­"Intensive fighting broke out. Our paratroopers sustained losses."

Two other Ukrainian soldiers were killed along with three people in Donetsk which was hit by the worst shelling in more than a week.

Mr Poroshenko called the ceasefire after his troops suffered big battlefield losses against the separatists in August which Kiev ascribed to the direct intervention of Russian forces.

Moscow, which opposes the pro-Western course pursued by the former Soviet republic, denies its troops have played any direct part in the conflict or armed the separatists despite what Kiev and ­Western governments say is incontrovertible proof.

Mr Poroshenko last week lauded the fact military clashes had diminished and military casualties had dwindled to zero, showing his peace plan was working.

He is seeking to calm the waters in the run-up to a parliamentary election next month from which he wants a mandate from pro-Western forces to press ahead with his plan to end the conflict and pursue reforms designed to make the country fit to join the EU.

The UN says more than 3,500 people had been killed in the conflict.