DONETSK, Ukraine — Ukraine pressed ahead Sunday with its military assault to stamp out pro-Russian separatists in the east of the country with its most intensive artillery bombardment of this rebel capital yet.
The attack with artillery and ground-to-ground rockets defied Russian threats to intervene here as the civilian death toll rose.
It also reinforced the Ukrainian leadership's rejection of a cease-fire on humanitarian grounds offered Saturday by the head of the main pro-Russian separatist group, the Donetsk People's Republic. The separatist leadership clarified Sunday that the cease-fire offer had covered only so-called green routes, or roads used by evacuees.
Still, Ukraine's rebuffing the proposal outright only added to concerns that Russia would intervene with what the authorities in Moscow are calling a humanitarian mission but which European nations and the United States would view as an invasion, analysts said. Secretary of State John Kerry has cautioned Russia against intervening on the "pretext" of providing aid.
On Sunday, artillery shells rained down on three districts of Donetsk, hitting a rebel checkpoint and leaving it swathed in smoke, but also striking houses, apartments and the maternity ward of the main hospital.
Shells killed at least one civilian. Roma Pronyakin, 37, was at home with his mother, watching TV, when their living room was struck. His mother, Alla, stood on the road in a state of shock.
"I had one son, and now I have none," she said.
The Ukrainian military said it had engaged in 30 firefights with the pro-Russian separatists in the past 24 hours.
"The terrorists who are still active in Donetsk and Luhansk regions should lay down their arms and not bring up empty conversations about cease-fires," the Ukrainian military spokesman, Anatoly Lysenko, said in Kiev, according to Ukrinform, the state news agency.