The commander of his Ukrainian armed forces eastern Donetsk it was replaced after Russian advances in the area, a military official said Saturday. Thus, the general Oleksandr Tarnavskiy will take over as head of the operational and tactical group, replacing the general Oleksandr Lutsenkothe official said in CNN.

The move comes after Lutchenko faced heavy criticism for failing to halt recent Russian incursions into his key city Pokrovsk.

Russian forces have been spotted just three kilometers (1.9 miles) from the city, according to Ukrainian mapping service DeepState.

Pokrovsk has been the site of some of the fiercest fighting on the eastern front for months as Russia tries to secure the city. It is located approximately 11 miles from the Donetsk and Dnipropetrovsk regions Ukrainianbeing a strategic target for Moscow.

Its fall to Russian forces would mark the biggest setback for Ukraine in months.