Seven Ukrainian soldiers were killed when separatist shelling hit their armoured vehicle near Donetsk airport in eastern Ukraine, a military spokesman said yesterday, 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.

“During the evening attack, the Ukrainian armoured transporter, with its crew and a paratroop unit, took a direct hit from a tank,” Lysenko told journalists.

“Intensive fighting broke out. Our paratroopers sustained losses,” Lysenko said, separately telling Reuters that seven soldiers had been killed. He said nine Ukrainian soldiers in all had been killed in the past 24 hours and 27 injured.

Under pressure from Western governments, 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.

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

“I do not have any doubt that the main, the most dangerous, part of the war is already in the past,” he told reporters.

Poroshenko is seeking to calm the waters in the run-up to a parliamentary election on October 26 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 European mainstream.

He will certainly want the ceasefire to be still holding at election time and a relatively calm atmosphere for people to cast their votes.