The basement in Bakhmut – the epicentre of Ukraine’s determined fight against Russia’s invasion – shakes from shelling above ground and a bloodied, pale soldier tumbles from the ambulance outside.

Soldiers rush to aid the medic treating the shrapnel-wounded serviceman but dash for cover when another Russian rocket crashes into a courtyard nearby, reverberating around abandoned housing blocs.

“Why am I so cold, doctor? I feel like I’m fading,” the soldier says, propped up on a mud-stained mattress as the medic works to halt the bleeding.

Courtyards beneath the artillery-scarred buildings were littered with twisted metal from bombed playgrounds, glass shards, and makeshift crosses over the graves of hastily buried civilians.

Ukrainian troops holed up in a network of dimly lit and cramped basements in the city’s western districts have been making a determined last stand against Russia in the longest and bloodiest battle of the war.

Fighting for the town, once known for its salt mines and sparkling wine production, has ground on for 10 long months.

Russia is posting incremental but costly gains, giving it control over some 80 percent of the devastated town.

“They don’t stop attacking day or night or day. Only when we hit them, they’re busy evacuating their wounded and killed,” said a deputy battalion commander, who identified himself as “Philosopher”.

“Little by little, they are nibbling away little pieces [of Bakhmut],” he added in an underground command post as shelling rumbled overhead.

Ukraine is defending street by street at a significant cost.

But it says it is mowing down waves of Russian forces and wearing out the enemy before launching its own large-scale strike back.

“On our side, we’re tired, people are exhausted,” Philosopher told the AFP news agency, describing how his forces from the 93rd brigade were coming within just 3 metres (10 feet) of Russian troops while weathering a constant barrage of artillery mortar and tank fire.

“[But] each day we resist here gives more opportunities for other units to prepare for a counterattack.”

The defence of the city – once home to some 70,000 people – is all the more precarious because there is just one road under Ukrainian control supplying the entrenched positions.

They call it “The Road of Life” but the burned-out vehicles discarded along the vital thoroughfare signal the deadly fighting on the horizon.

Charred trees line the 25km (16-mile) road from the nearest Ukrainian-controlled hub, and civilian cars and military hardware careen down the muddied route to bring new fighters in and extract the injured.

“You could call it the road of life or the road of death,” 22-year-old Amina, a woman serving in the military for several months, said while sheltering in a basement on Bakhmut’s outskirts.

President Volodymyr Zelenskyy said last month Bakhmut’s fall would give Russian forces an “open road” to the rest of the war-battered Donetsk region, which Moscow claims is Russian land.