The Pokrovsk direction remains the key vector of the Russian offensive, where Russia has concentrated most of its troops, said Victor Tregubov, a spokesperson for Ukraine's Khortytsia group of forces.

After Russian forces first approached the outskirts of Pokrovsk in fall, this proud coal-mining city in Donetsk Oblast became the rock upon which the Russian army dashed itself against. After months of fighting and making advances from both east and west,