Shelling batters Ukraine’s east amid reports that Russia’s offensive may be foundering

LVIV, Ukraine — Russian forces aimed a punishing artillery barrage Saturday at cities, towns and villages in eastern Ukraine, even as Western and Ukrainian military officials and analysts said Moscow’s much-vaunted military offensive in the country’s industrial heartland was being slowed by troop casualties and logistical, supply and morale problems.

Russia reported nearly 400 artillery strikes overnight and early Saturday, mainly in the eastern battle zone. It described the targets as military ones, but Ukraine says residential areas, including the northeastern city of Kharkiv, are being ravaged.

At the same time, the Kremlin redoubled efforts