Shelling killed six people and wounded 15 others in the rebel stronghold of Donetsk, the city council said Monday — the worst reported violence since a cease-fire between Russian-backed rebels and Ukrainian troops took effect on Sept. 5.
Nonetheless, the cease-fire deal has brought some normalcy to parts of eastern Ukraine and allowed prisoners on both sides to go home.
Another 73 Ukrainian soldiers were freed Sunday night in an exchange with the rebels, Col. Andriy Lysenko, spokesman for the Ukrainian National Security and Defense Council, said Monday. Donetsk rebel leader Andrei Purgin was quoted by Interfax news agency as confirming that 73 rebels had been released in return. It was the largest reported prisoner exchange amid the fighting that began in mid-April.
Fighting around Donetsk's government-held airport has left many northern neighborhoods in the crossfire. Over the weekend, Ukraine said its troops repelled an attack of 200 rebel fighters, but suffered no military casualties.
Two northern neighborhoods in Donetsk were shelled heavily Sunday, leading to the casualties and damaging both homes and offices, the city council said.
While the neighborhoods hit by shelling are under the control of the rebels, the Ukrainian government blamed the militants for the civilian casualties.
"Neither today nor yesterday nor in the previous days did Ukrainian forces shell any residential areas and settlements," Lysenko said in Kiev on Monday.
Observers from the Organization for Security and Co-operation in Europe, who are overseeing the implementation of the cease-fire, said Sunday they were 200 meters (650 feet) away as four shells burst in Donetsk. The team saw one woman lying on the ground.
The first civilian casualties in Donetsk underscore how fragile the peace may be. Both sides have made it clear that they are rearming in case the fighting starts anew.
Ukrainian Defense Minister Valeriy Heletey told Channel Five that the delivery of weapons from NATO countries, agreed upon earlier this month, was "underway." Those comments were also made by another senior official but later denied by four of the five NATO countries he had mentioned.
On Monday, Poland's Defense Minister Tomasz Siemoniak said while Poland is not currently selling arms to Ukraine, an arms deal will be the theme of talks when Heletey visits Warsaw this month. He offered no date for the visit.
The fighting in eastern Ukraine began a month after Russia annexed the Black Sea peninsula of Crimea in March. It has claimed at least 3,000 civilian lives and forced hundreds of thousands to flee, according to the U.N.