The boom of incoming artillery fire from the Ukrainian position sends the pro-Russian rebels scrambling for cover.
"Everyone into the trenches!" yells separatist commander Zhigan as firing rumbles around.
"That one's a Grad missile. And that one is a 120-millimetre mortar," he says with expertise as he crouches behind sandbags for protection.
Before the brutal conflict in east Ukraine, Zhigan - whose nickname roughly translates as 'artful dodger' - sold fruit and vegetables in the nearby village of Frunze.
Now he leads some twenty frontline fighters who for the past week have been part of a tightening noose around a small deployment of Ukrainian troops clinging to a strategic checkpoint close to the rebel bastion of Lugansk.
"The Ukrainian soldiers are some two kilometres from here. They're holding checkpoint 31," Zhigan says.
"They are almost entirely surrounded. They have no chance but they keep on firing day and night."
Despite a nominal ceasefire in place since early September, deadly clashes have raged on at flashpoints across the war-torn region where rebel fighters are trying to mop up pockets of Ukrainian resistance.
Zhigan hopes that the government troops holed up at checkpoint 31 will listen to a blunt offer the rebels have made them: abandon their posts if they want to save their lives.
That is exactly what their comrades at a nearby checkpoint, number 32, decided to do last week after a ferocious rebel onslaught.
"Yesterday we sent a taxi driver with a white flag to pass on our proposal but they didn't except it - for the moment," the insurgent commander says.
Sheltering in his trench with AFP journalists, he calls around neighbouring rebel positions to check if any have been hit in the latest bombardments.
Then his men unleash a barrage of rocket fire back at the Ukrainians.
Gradually the shooting dies down and the rebel fighters emerge from their shelters and observe the enemy position through their binoculars.
"We have not had any dead on our side," since the start of the fighting, says insurgent Misha, 22, taking off his helmet and making the sign of the cross.
