In the courtyard of a farmhouse now home to soldiers of the Ukrainian army's 47th mechanised brigade, I'm introduced to a weary-looking unit by their commander Captain Oleksandr "Sasha" Shyrshyn.

We are about 10km from the border with Russia, and beyond it lies the Kursk region Ukraine invaded in the summer - and where this battalion is now fighting.

The 47th is a crack fighting assault unit.

They've been brought to this area from the fierce battles in the country's eastern Donbas region to bolster Ukrainian forces already here.

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Captain Shyrshyn explains that among the many shortages the military has to deal with, the lack of infantry is becoming a critical problem.

Sasha is just 30 years old, but he is worldly-wise. He used to run an organisation helping children in the country's east before donning his uniform and going to war.

He is famous in Ukraine and is regarded as one of the country's top field commanders, who isn't afraid to express his views on the war and how it's being waged.

His nom de guerre is 'Genius', a nickname given to him by his men.

'Don't worry, it's not a minefield'

Sasha invited me to see one of the American Bradley fighting vehicles his unit uses.

We walk down a muddy lane before he says it's best to go cross-country.

"We can go that way, don't worry it's not a minefield," he jokes.

He leads us across a muddy field and into a forest where the vehicle is hidden from Russian surveillance drones that try to hunt both American vehicles and commanders.

Sasha shows me a picture of the house they had been staying in only days before - it was now completely destroyed after a missile strike.

Fortunately, neither he, nor any of his men, were there at the time.

"They target commanders," he says with a smirk.

'The world is scared of Russia'

It takes me a moment or two to realise we are only a few steps away from the Bradley, dug in and well hidden beneath the trees.

Sasha tells me the Bradley is the finest vehicle he has ever used.

A vehicle so good, he says, it's keeping the Ukrainian army going in the face of Russia's overwhelming numbers of soldiers.

He explains: "Almost all our work on the battlefield is cooperation infantry with the Bradley. So we use it for evacuations, for moving people from one place to another, as well as for fire-covering.

"This vehicle is very safe and has very good characteristics."

Billions of dollars in military aid has been given to Ukraine by the United States, and this vehicle is one of the most valuable assets the US has provided.

Ukraine is running low on men to fight, and the weaponry it has is not enough, especially if it can't fire long-range missiles into Russia itself - which it is currently not allowed to do.

If President-elect Donald Trump cuts the supply of military aid, the Ukrainians will lose - it's that simple.

Sasha says: "We have a lack of weapons, we have a lack of artillery, we have a lack of infantry, and as the world doesn't care about justice, and they don't want to finish the war by our win, they are afraid of Russia.

"I'm sorry but they're scared, they're scared, and it's not the right way."

Like pretty much everyone in Ukraine, Sasha is waiting to see what the US election result will mean for his country.

He is sceptical about a deal with Russia.

"Our enemy only understands the language of power. And you cannot finish the war in 24 hours, or during the year without hard decisions, without a fight, so it's impossible. It's just talking without results," he tells me.

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'Losing will be not only our problem'

These men expect the fierce battles inside Kursk to intensify in the coming days.

Indeed, alongside the main supply route into Kursk, workers are already building new defensive positions - unfurling miles of razor wire and digging bunkers for the Ukrainian army if it finds itself in retreat.

Sasha and his men are realistic about support fatigue from the outside world but will keep fighting to the last if they have to.

"I understand this is only our problem, it's only our issue, and we have to fight this battle, like we have to defend ourselves, it's our responsibility," Sasha said.

But he points out everyone should realise just how critical this moment in time is.

"If we look at it widely, we have to understand that us losing will be not only our problem, but it will be for all the world."

Stuart Ramsay reports from northeastern Ukraine with camera operator Toby Nash, and producers Dominique Van Heerden, Azad Safarov, and Nick Davenport.

(c) Sky News 2024: Ukrainian frontline commander warns: 'The world is scared of Russia and losing is not onl