Violence flared in Odessa today as pro-unity and pro-Russia demonstrators clashed during a rally. According to the Ministry of the Interior, 31 people died after being chased into the trade union building and a fire started during the chaos.

Most of the victims were asphyxiated but some jumped from windows to escape. The ministry confirmed that another 50 people were injured, including 10 policemen.

The bottom two videos were uploaded to YouTube by Vitaliy Umanets.

Then in Sloviansk, the heartland of the pro-Russia rebels who now control large pockets of the country’s east, locals were awoken this morning by the sound of gunfire as Ukraine’s army launched a long-awaited counter-terrorist offensive “They were shooting from over there,” one pensioner told VICE News as she pointed to the fields beyond her garden gate.

“If I could I would rip the Ukrainian army to shreds with my teeth,” 35-year-old builder Vasily snarled to VICE News. In the distance black clouds mass and lightning flashes. Just a few miles from Vasily's village, Ukrainian armored personnel carriers line the road. Kalashnikov-clasping soldiers sit atop the heavyweight military vehcles. “Don’t go that way, it's war!” shouted one old man sitting on a bench outside the village shop.

According to eyewitnesses, armored vehicles and scores of paratroopers moved in during the early hours of the morning reportedly destroying nine outlying insurgent roadblocks and taking up position a few miles away from the entrance to the town. Pro-Russia forces have reported at least one fatality, though more are expected.

The rebels say they will not back down. 'We will fight for our city until the very end. We’ve been preparing for this for weeks.'

The Ukrainian attack did not go unchallenged, however. As the pro-Russia militia was driven back, they responded with expert marksmanship and shot down at least two military helicopters circling the city.

The Ukrainian army has slowly inched their position forward on the main roads surrounding the rebel-held city over the last week. Despite this, just 60 miles away in Donetsk, the pro-Russia rebels seized another key strategic point — a railway control center. The move brought the region’s train network grinding to a halt.

Following the start of the assault on Sloviansk, Vyacheslav Ponomarev, the city’s self-appointed “people's mayor,” declared a state of emergency. Swapping his trademark tracksuit top for military fatigues and a bulletproof helmet and vest, the mayor warned women and children to stay inside and called on all local men with arms to come to the barricades and defend the city. Churches bells rang to signal the alarm as the Russian flag fluttered from the steeple.

The operation is being met with fierce anger by many locals, who felled trees on main roads in a bid to hold back the Ukrainian army’s advance. The gauntlet of trunks means the city is nearly totally inaccessible by road. A handful of people braved the pouring rain to escape the city by foot before nightfall.

The rebels say they will not back down. “We will fight for our city until the very end,” Yevgeniy, a 35-year-old camouflage-clad local militia commander, told VICE news. “We’ve been preparing for this for weeks."

Most western media were unable to enter the besieged city today. Journalists working for outlets including Sky News, CBS, and Buzzfeed were detained, roughed up, and later released by pro-Russia forces as they attempted to enter the city. The region has become increasingly difficult to operate in as hostage taking has become part of the rebels’ war strategy. Seven OSCE military observers, a civilian translator, and several local journalists and activists have been snatched from the city’s streets in the past week. Their condition is unknown.

The fear in the city is palpable.

Two previous attempts to dislodge the rebels have ended in failure when Ukrainian troops either surrendered or were captured by the pro-Russia militia operating in the area. Kiev’s control over its security forces has been called into question as local police across the region have defected to the rebels’ side.

At a Ukrainian military checkpoint on the city’s southeast an angry mob surrounded the soldiers: “Why are you here? Will you shoot your own people?” “We will not attack, we will not shoot,” replied the tense soldier, clasping an AK47 to his chest.

Many fear that this “counter-terror” assault will tip troubled Ukraine over into civil war. Rebels now control large pockets of the east of the country including Donetsk, Luhansk and Mariupol. But the region remains deeply politically divided.

In Sloviansk, the rebels established tightly controlled tire blockades on every entrance into the city. The opposing forces are separated by just a few miles of tarmac. The next wave of attack, if it comes, is expected imminently.

The fear in the city is palpable. As dusk fell the streets were near empty and the few vehicles that dared venture out drove slowly with their hazard lights flashing. A strict curfew between midnight and 6 AM has been imposed by the rebels since two of their men were shot dead by unknown assailants on Easter Sunday.

Locals are reporting difficulties in obtaining basic supplies. Ana, a 69-year-old pensioner, told VICE News she had only ventured outside her house to try and buy bread. “We have been inside for two days, now we have no food left,” she said. “This is situation is terrible, we don’t know where to turn.”

As night drew in armed men in ragtag military gear and gangs of menacing thugs roamed the streets searching for provocateurs and spies. A "no lights" policy was imposed after dark as gunfire crackled through the streets.