There is no doubt Ukraine has been losing ground in this key city in the east. For Russia, Pokrovsk is another stepping stone towards its goal of taking control of all of the Donbas. But Ukraine needs to prove it is still capable of resisting.

At a Ukrainian command post, well behind the front line, orders are relayed by radio in rapid and quick succession. Soldiers watch dozens of live drone feeds. They are coordinating strikes on Russian positions inside the city. The commander of the Skala Assault Regiment, Yuri, is keen to prove to us that Ukraine still controls the north of the city - to show that the Kremlin's claim that it has taken Pokrovsk is a lie. Over the radio, they ask two of their soldiers to break cover from a building to display a Ukrainian flag. They move quickly to avoid being spotted. The drone feed shows the moment they briefly wave their yellow and blue flag, before quickly returning to cover. Yuri tells me: "You've now seen it with your own eyes." "I think the whole world should know we will not just give up our territory," he says. "If we do not show this, everyone will lose faith and stop helping Ukraine."

The battle for Pokrovsk, once a key logistics hub for Ukraine's military, has been grinding on for nearly 18 months. The city is already in ruins. The question now is how much longer can Ukraine hold on. Those tracking the Russian advances suggest Ukrainian forces barely have a hold on the city. Russian forces have slowly been advancing from the south. Ukraine is losing ground, but says it still holds the north, up to the railway line that bisects the city. (BBC)