DONETSK, Ukraine -- After days of street battles and weeks of shelling, Ukrainian troops made a significant push Wednesday into rebel-held territory, claiming control over a large part of the separatist stronghold of Luhansk and nearly encircling Donetsk, the largest rebel-held city.
The advance of the Ukrainian army against pro-Russian separatists comes as the civilian death toll is mounting from sustained artillery strikes, and rebel cities are slipping into a humanitarian disaster. At least 52 deaths were reported Wednesday, along with 64 wounded -- and due to the dangers of the eastern Ukraine war zone, no deaths were reported from Luhansk, meaning the actual toll could be even higher.
Ukrainian troops have been trying for weeks to drive the rebels out of Luhansk and cut off Donetsk, a city of 1 million that has shrunk by a third, as frightened residents fled. In the past few days, several Donetsk neighborhoods have been hit with sustained artillery fire, and fighting on the city's outskirts has become more intense.
The death toll mounted quickly Wednesday. In the Donetsk region, 43 locals were killed and 42 wounded in less than two days, including in two deadly artillery attacks Wednesday afternoon in the capital of Donetsk, local authorities said. In addition, nine soldiers died and 22 were wounded in fighting in a town outside Donetsk.
Luhansk city authorities reported running battles between the two sides. By early evening, government forces took control of "significant parts" of Luhansk, an eastern city just 12 miles from the Russian border, said Andriy Lysenko, a Ukraine's National Security Council spokesman.
A Ukrainian SU-25 plane was also shot down near Luhansk, Mr. Lysenko told TV station 112 late Wednesday. He said the pilot's location was still unknown.
Hard-hit Luhansk has been without electricity, running water or phone connections for 18 days because of the fighting. Russia has sent a massive aid convoy to help residents there, but it is still stuck at the border, not yet approved by Kiev because its proposed route lies through rebel-held territory. Ukraine has accused Russia of arming and supporting the separatists, a charge that Russia denies. Ukraine and the West fear that the massive aid convoy, more than 200 trucks, will be used in some way to help the separatist militia.
Donetsk, meanwhile, has come under daily shelling attacks from all sides. Wednesday morning, rockets slammed into residential areas, including the Donetsk suburb of Makiivka. More rockets hit in the afternoon.