Electrical wires hang loose and the wreckage of a burnt-out car is stopped dead in the middle of the road in Donetsk's Leninsky district. Inside trolley bus number 17 is a mess of smeared blood and shattered glass.

Locals gathered at the scene said that several rounds of what they believed were mortars hit the area at around 9am local time this morning. Around the corner, a tram had also ground to a halt after the track in front of it was caved in by another shell.

Officials said eight people were killed at the scene and another five died en route to hospital following the morning strike on the city, the heart of rebel-held east Ukraine. Another 20 people were reportedly injured in the incident according to local news agencies.

Horrific scene this morning in Leninsky district up to 13 killed in trolley bus shelling — Harriet Salem (@HarrietSalem)January 22, 2015

Photo by Harriet Salem

Rebels guarding the scene said that a Ukrainian diversionary group operating inside the rebel-held territory had carried out the attack, but VICE News could not verify this information.

A statement released by the Ukraine Ministry of Defense says that the "facts suggest terrorists fired" at the public transport vehicle. The statement also says that the Kiev government "wish to emphasize" that Ukrainian servicemen "will never use weapons against civilians."

Andriy, 31, who was standing just one block from the shelled bus, said he ran for cover inside a grocery store when he heard the first rounds come in. "I heard at least five (shells), people were on their way to work, the shops were open," he told VICE News. "There are no rebel positions here, it's a civil area. I didn't want to fight before, but now, after this, I am considering joining them (the rebels)."

This morning's incident occurred just hours after new round of diplomatic talks between representatives from Ukraine, Russia, France, and Germany concluded in Berlin; shattering already tenuous hopes for a new peace deal.

Meanwhile, Ukrainian military forces have reportedly pulled out of Donetsk airport, though skirmishes continue in the area around it. This withdrawal came on the back of a heavy death toll — 10 soldiers were killed in the preceding 24 hours of fighting, according to defense officials, while 16 were wounded.

Last week, 12 people were killed in public bus passing through a Ukrainian checkpoint in Volnovakha by what the OSCE say, based on analysis of impact craters, were "rockets fired from a north-north-eastern direction." This statement implies that rebel forces fired the deadly rounds.

There has been a sharp spike in fighting, and casualties, in eastern Ukraine over the last two weeks as clashes have reignited all along the frontline and shells are hitting Donetsk city center again for the first time in months.

Photo by Harriet Salem

"We are seeing nearly as many casualties as in the worst months of summer. We are now in one of the worst periods of the conflict since it began," Donetsk morgue Director Dmitry Klashnikov told VICE News. "But the casualties are even higher now than before because a lot of people that fled have returned — children, families, and students," he added.

According to statistics provided to VICE News by the morgue, 157 casualties have been recorded in Donetsk since the beginning of January, with 119 of these occurring in the last two weeks.

The escalating violence and mounting death toll is deepening the divide between the local population in rebel-held and government-controlled territories.

Footage released on a pro-rebel television station NovoRossiya shows what appears to be a Ukrainian prisoner war being brought to the bloody scene of the bus shelling and surrounded by an angry crowd. Escorted by armed men and handcuffed the prisoner has a bruised face and remains silent as television crews and shouting locals surround him. Eventually he is bundled into a car and escorted away from the scene with his head bowed as enraged locals start kicking and punching him in the back and head.

Another 18 military prisoners were reportedly also taken to the scene, accompanied by the head of the self-proclaimed People's Republic of Donetsk Alexander Zakharchenko.

Today also marks Ukrainian "Unity Day," a state holiday that celebrates the signing of the Act Zluky agreement which united east and west Ukraine in 1919. During a speech he made to mark the day, Ukrainian President Petro Poroshenko said: "No one would ever be able to undermine our unity."

VICE News' Sally Hayden contributed to this report.