Fighting has stopped an international police team from reaching the crash site of a Malaysian Airlines plane for a second day running.
A delegation of Australian and Dutch police and forensic experts stopped in Shakhtarsk, a town around 20 miles from the fields where the aircraft was downed.
Sounds of regular shelling could be heard from Shakhtarsk and residents were fleeing the town in cars.
A high-rise apartment block in the town was hit by at least two rounds of artillery, according to reports.
The mandate of the police team is to secure the currently rebel-controlled area so that comprehensive investigations can begin and any remaining bodies can be recovered.
With government troops intensifying their push to claw back more territory from pro-Russian separatist rebels, the death toll is mounting steadily.
United Nations figures show more than 1,100 people have died in just over four months of fighting.
Ukraine has accused rebels of tampering with evidence and trying to cover up their alleged role in bringing the Malaysia Airlines plane down with an anti-aircraft missile.
Separatist officials have staunchly denied responsibility for shooting down the airliner and killing all 298 people onboard.
A Ukrainian security spokesman said data from the recovered flight recorders shows Malaysia Airlines Flight 17 crashed due to a massive, explosive loss of pressure after being punctured multiple times by shrapnel.
Andrei Lysenko said the plane suffered "massive explosive decompression" after it was hit by fragments he said came from a missile.
The data recorders were sent to UK experts for examination.
In their campaign to take control over more territory from separatist forces, Ukraine's army has deployed a growing amount of heavy weaponry.
Rebels have also been able to secure large quantities of powerful weapons, much of which the United States and Ukraine maintain is being supplied by Russia.
Moscow denies the claims.
The UN High Commissioner for Human Rights said in a report that at least 1,129 people have been killed between mid-April, when fighting began, and July 26.
The report said at least 3,442 people had been wounded and more than 100,000 people had left their homes. A UN report from mid-June put the death toll at 356.
At least eight civilians were killed by fighting and shelling in two cities held by separatist militants overnight on Sunday, officials in the region said.
Authorities in Luhansk said that five people were killed and 15 injured by overnight artillery strikes. Three were killed in Donetsk as a result of clashes.