Ukraine shelling kills 6, tests cease-fire

KIEV, Ukraine -- Shelling killed six people and wounded 15 others in rebel-held Donetsk, the city council reported Monday -- the worst violation yet of the cease-fire between Russian-backed rebels and Ukrainian troops that took effect Sept. 5.

For the first time, international observers from the Organization for Security and Co-operation in Europe (OSCE) said they had "taken fire" as the shelling erupted around the city.

Two northern neighborhoods were heavily shelled Sunday, leading to the casualties and damaging both residential and administrative buildings, the council said.

Fighting centered on 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.

Observers from the OSCE said they were 650 feet away from four shells exploding Sunday in Donetsk. The team saw one woman lying on the ground, and said a rebel fighter on the scene told them four people had been killed that day.

Another shell exploded close to the team as they moved to a different location, prompting them to leave the area, according to a spokesman interviewed by the Reuters news agency.

"All six colleagues were able to get back to base but both vehicles were badly damaged," spokesman Michael Bociurkiw told Reuters. "We regard this as a very serious incident. It's the first time our vehicles have taken fire."

The government has not confirmed the number of casualties.

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.