An artillery shell or mortar struck a public transport stop in the rebel-controlled city of Donetsk in eastern Ukraine yesterday, killing at least eight civilians in an incident both sides blamed on the other.

The missile strike, which wrecked a trolleybus and blew out windows nearby, followed a night of intense fighting at the city’s main airport and diplomatic talks in Berlin involving Ukraine and Russia.

President Petro Poroshenko, returning early from Switzerland where he told the World Economic Forum that Russia now had 9,000 troops inside Ukraine, said he and defence chiefs would work on a plan to “regroup and stop aggression”.

“We’ll decide how to stop the operation of terrorist forces and Russian regular troops,” he said in an online statement. Rebel leader Alexander Zakharchenko urged local residents to gather at the scene of the trolleybus attack, promising them the opportunity to confront captured Ukrainian servicemen.

Ukraine forces have withdrawn from Donetsk airport’s new terminal

Separately, video footage showed a handcuffed Kiev prisoner being shouted at and punched by civilians near the trolleybus.

Military spokesman Vladislav Seleznyov said 10 Ukrainian soldiers were killed overnight, six at the airport complex, a symbolic target where a small group of government defenders have been holding out against Russian-backed separatists for months. The spokesman later said government forces had withdrawn from the airport’s new terminal, the core of the complex.

“We left the new terminal because it looks like a sieve and there’s simply nowhere to hide there,” Seleznyov said.

It was not clear what sort of missile hit the trolleybus or who fired it. Each side blamed the other.

A video clip showed the hulk of the trolleybus with its windows blown out and smoke pouring from a nearby passenger car.