To surround the eastern fortress city of Pokrovsk from the south, Russian forces first have to roll back Ukrainian defenses in Kurakhove, a village on the bank of the Vovcha River 18 miles south of Pokrovsk in eastern Ukraine’s Donetsk Oblast.

The Ukrainian army’s 33rd Mechanized Brigade and its German-made Leopard 2A4 tanks stand in their way. On Monday, a powerful Russian force rolled toward Dalnje, just south of Kurakhove, clearly aiming to fight its way through the former in order to bypass and cut off the latter.