The panting Ukrainian soldier gripping a Kalashnikov with fear blazing in his eyes had not moved a step from his roadside ditch for five hours.

A Russian tank hiding near the horizon was firing at will after setting its sights on a spot near which 55-year-old Andriy lay face down in the dirt.

His bronzed neck was layered with sweat and his mouth was too dry to speak in more than a hoarse whisper.

Russian forces have advanced enough to target a crucial road linking several east Ukrainian cities with mortar and artillery fire Russian forces have advanced enough to target a crucial road linking several east Ukrainian cities with mortar and artillery fire Photo: AFP / ARIS MESSINIS

But his heart was racing so hard that he struggled to catch his breath in the absolute stillness of the east Ukrainian front.

"Who can stop this war?" he pleaded after squinting from the whistle of another shell fired by encroaching Russian forces three months into their invasion of Ukraine.

The blast shot a towering pillar of dirt into the sky on the opposite side of the road from the lonely soldier.

The charred remains of Ukrainian military vehicle litter a road under assault from Russian forces trying to cut off a swathe of the eastern front The charred remains of Ukrainian military vehicle litter a road under assault from Russian forces trying to cut off a swathe of the eastern front Photo: AFP / ARIS MESSINIS

More followed in a steady staccato a handful of metres above his cowering head.

Andriy had no idea where the other men in his unit had gone -- or how close the Russians had come to his ditch.

"Our guys have stopped firing back," he whispered again after glancing up and down the road.

"We do not want to provoke them because then the Russians will start shooting at us even harder."

Ukrainian soldiers setting off for the front often express a mixture of pride and keen awareness of the monumental danger Ukrainian soldiers setting off for the front often express a mixture of pride and keen awareness of the monumental danger Photo: AFP / ARIS MESSINIS

The shells whizzing over Andriy's head are in danger of cracking Ukraine's desperate defence of a major stretch of the eastern front.

Ukrainian soldiers often carry gas masks because of the risk of fighting in an industrial region filled with oil refineries and chemical plants Ukrainian soldiers often carry gas masks because of the risk of fighting in an industrial region filled with oil refineries and chemical plants Photo: AFP / ARIS MESSINIS

The two-lane road once formed a lifeline by which Ukraine sent reinforcements up to the besieged industrial cities of Lysychansk and Severodonetsk.

Andriy was learning the hard way that Russian tanks had now crept close enough to effectively sever the supply line.

The Russian guns hidden in the rolling hills were methodically firing at every vehicle they could spot racing down the road.

Ukraine is throwing some of its toughest forces to the front to try and keep the Russians from severing a key supply route Ukraine is throwing some of its toughest forces to the front to try and keep the Russians from severing a key supply route Photo: AFP / ARIS MESSINIS

Charred carcases of obliterated vans and military machinery littered stretches of the debris-strewn highway.

A few dozen Ukrainian soldiers oozed with nervous energy further south down the road as they prepared for the perilous mission of somehow holding off the Russian advance.

"I have lost a lot of friends," a soldier who uses the nom de guerre Gere said before hopping into an armoured vehicle and rolling off toward the Russian line of fire.

"I want to avenge their deaths," the 23-year-old said.

'Who can stop this war,' the Ukrainian soldier pleaded after being pinned down to the same spot for five hours by exploding Russian shells 'Who can stop this war,' the Ukrainian soldier pleaded after being pinned down to the same spot for five hours by exploding Russian shells Photo: AFP / ARIS MESSINIS

Sergeant Galyna Syzonenko is all too familiar with the desperation of being pinned down in a trench.

The military doctor was holding a walkie-talkie and listening to the soul-crushing booms of huge weapons exploding in a verdant hill that the Russians have been trying to seize for the past week.

She would get the call during the first respite to speed over in her van and bring out the wounded.

Chances were high that the 50-year-old would end up trapped there for days on end.

"It is incredibly frightening," she said of trench warfare.

"There are times when you cannot move for hours. You cannot even dare to look up. You can spend six or seven hours like that."

The walkie-talkie was still silent and the battles overhead seemed to be only gathering pace.

"I wear my fear like a badge of honour," said the sergeant.

"Only the foolish have no fear in such situations."

Captain Oleg Marchenko seemed to withdraw deep inside himself in search of words to express his thoughts under unrelenting fire.

The 28-year-old eventually looked at the sergeant and smiled.

"She sits in the trench and worries about saving others," Marchenko said.

"A tank gets specific coordinates and then keeps hitting that spot over and over. It can fire 1,000 shells in a day," he said with a distant look.

"If you move a step, you die."

Marchenko and Syzonenko stepped a little further back from the curb to let a truck carrying an armoured vehicle roll off into the battle-engulfed hill.

"As long as you have a trench or a ditch, you can still save your life," said the captain. "And lying there, you feel fear and adrenaline both."