Two teenagers died and four were wounded Wednesday, Nov 5, when an artillery shell hit a school playing field as they played football in eastern Ukraine, BBC News reports.

The attack in Donetsk came as both sides in the Ukrainian conflict accused each other of tearing up a peace deal.

A fragile ceasefire has been in place since Sept 5, although hundreds of people have been killed since then.

Fighting erupted in April after pro-Russian militias seized control in the regions of Donetsk and Luhansk.

More than 4,000 people have died in eastern Ukraine since the conflict began and the European OSCE monitoring mission has warned that the "bloodletting" is still going on, with numerous incidents of shelling.

The shell landed close to Donetsk airport at a school which was rebuilt by one of Ukraine's richest men, steel billionaire Rinat Akhmetov, and reopened last year.

The head of Akhmetov's humanitarian fund, Rimma Fil, told the BBC that the children had been playing football after lunch when the shell exploded on the pitch.

The four wounded teenagers were being treated in intensive care, she said. Akhmetov described the attack as a terrible tragedy and appealed for an end to the violence.

Shelling in Donetsk intensified on Tuesday night and there were reports earlier on Wednesday of one civilian killed and several others wounded in mortar attacks.

The area around Donetsk airport has seen some of the worst violence in the weeks since the ceasefire was declared. Four adults were killed at another school near the airport a month ago, on the day children returned to school after an extended summer break.