Russian forces will push into the heart of Ukraine if they succeed in capturing the frontline town of Chasiv Yar and the wider Donbas region, a Ukrainian governor has warned.

Vadym Filashkin, governor of the Donetsk region, told Sky News his country's soldiers would not allow this to happen and would do "everything possible - and impossible" to push the Russian invaders back. But he said Vladimir Putin's troops were attempting to break through eastern Ukraine's defensive lines, with between 1,500 to 2,500 artillery rounds and airstrikes fired in the region daily.

Ukraine war latest: 'Undeclared Russian military intelligence officer' expelled from UK Asked what the danger was for Ukraine and the world should the whole of the Donbas fall under Russian control, Mr Filashkin said: "The enemy will move onwards. If, God forbid, this happens, the enemy will advance further into the central territory of our country.

"We will not allow this and we will do everything possible - and impossible - to hold the enemy here in the Donetsk region and restore the borders to those of 1991." He was referring to when Ukraine gained its independence from the then Soviet Union. The governor said about 2,500 civilians in his region alone had been killed and almost 5,000 injured since Russia launched its full-scale invasion in February 2022.

"Words to describe all the anger that we feel have probably not been invented yet," he added. Mr Filashkin was speaking close to a giant Ukrainian flag flying over a park in the city of Kramatorsk, the main administrative hub for the area and a vital military stronghold.

Kramatorsk - along with other eastern cities such as Konstantinivka and Slovyansk - would be at risk of much greater bombardment should Russian forces capture Chasiv Yar. The town's vantage point, on top of a hill, would put a larger area in range of Russian artillery.

Read more:Russia steps up attacks on energy facilities in UkraineRussia's Victory Day parade can be summed up by pain, pride and propaganda Much of the town lies in ruins Kyiv had claimed Moscow wanted to capture Chasiv Yar ahead of Russia's annual 9 May Victory Day celebrations to commemorate the defeat of Nazi Germany in the Second World War. But Ukrainian forces are still in control, though much of the town lies in ruins with all but a few hundred residents long since evacuated.

Hidden in a blossoming treeline a few miles from the edge of Chasiv Yar, a small Ukrainian drone team from 22nd Brigade of the Ukrainian Armed Forces watched the smoke from Russian airstrikes rise over the town on Wednesday. The commander of the unit - who gave his callsign as "Steve" - said Russian attacks had been intensifying every week for the past three to four months as Moscow tried to take advantage of a delay in Western weapons resupplying Ukrainian positions.

'As brutal as you can imagine' Questioned on what the situation was like for the defending Ukrainian forces, he said: "It's very intense. It's very brutal.

Yeah. As brutal as you can imagine.

And even more." Speaking in near-fluent English with an American accent, he said Ukraine needed many more precision-guided weapons from their Western partners. "That would change the war, like, completely, because we know where they [the Russians] are.

Like, exactly. We need just a weapon to destroy them.

That's it," he added. Drone unit hunts Russian mortar team Suddenly, his team receives a call to send up their reconnaissance drone - called Leleka, which means "stork" in Ukrainian - to hunt for a Russian mortar team inside Russian-held territory to the east of Chasiv Yar.

The aircraft, which looks like a large grey model aeroplane, is launched by hand from a giant rubber catapult in a field. It flies at a height of about 1,000m and has a range of around 20 miles so can penetrate deep behind enemy lines, provided it is not disrupted by jamming devices.

Once it is airborne, Steve and two colleagues sit in a mobile cabin, with one person piloting the drone and the other two scanning a live camera feed for signs of enemy forces. "Our main task is to give information.

So, we are flying behind the backs of the Russians. We see what they're doing over there.

Are they collecting any forces? The gathering? Where do they have artillery? Howitzers?," the drone commander said. "We spot them, we pass the information to the higher command and they find the means to demolish them." The team quickly identifies what they believe to be the mortar position, along with ammunition and two Russian soldiers - they relay the information back to their headquarters - before guiding the drone back in to land.

"You are trying to spot somebody who's hiding," said Steve. "It's like a kid's game, you know? But, with the weapons, everything is serious here.".