Russia is slowly grinding through the Donbas as Ukraine braces for a brutal fight over its last strongholds

A Ukrainian soldier looks out of a window of an apartment destroyed by shelling in the direction of Kostiantynivka.

Alex Nikitenko/Global Images Ukraine via Getty Images Russia is advancing slowly through the Donbas as Ukraine prepares to defend its last major strongholds.

Ukrainian commanders say the fight for Kramatorsk and Sloviansk could become brutal battles of attrition.

Analysts warn the outcome may hinge on Ukraine's ability to keep troops supplied under relentless drone and air attacks.

There is a moment before the camera begins rolling when the young Ukrainian commander says, "History is repeating itself for us in the Donbas.

Unfortunately." Then he falls silent.

A few minutes later, the man, known by the call sign "Fleshka," takes a seat on a weight bench in the garden of a house in an eastern Ukrainian village, just a 30-minute drive from the nearest Russian troops.

Every morning, he benches 80 kilograms here before returning to the screens where he coordinates the destruction of Russian assault units through the live feeds from his drone operators.

"I hope it will be a long fight.

This is our land, and we will fight for every meter of it," Fleshka says once the camera is rolling.

A few meters away stands his comrade "Sascha," another unit commander with the 33rd Brigade.

"It's going to be a brutal meat grinder," he predicts, describing a bloody war of attrition.

"But I'm glad to be part of it." Fleshka, 24, and Sascha, 26, belong to a new generation of young Ukrainian commanders helping lead the defense of the last Ukrainian-held bastions in the Donbas.

Both have spent years fighting on the front lines.