DONETSK, Ukraine - Fighting between government forces and pro-Russian rebels left at least 10 civilians dead in eastern Ukraine on Sunday as an international probe at the crash site of downed flight MH17 made headway.
The deputy mayor in the encircled insurgent stronghold of Donetsk told AFP that shooting in a residential suburb had killed six civilians and injured 13, the latest victims of more than three months of civil war that has claimed at least 1,150 lives.
Local authorities in the second-largest separatist bastion of Lugansk said shelling had left three dead and eight injured, while the city council in the frontline rebel base of Gorlivka reported one dead and 16 injured in clashes there.
Ukraine's military said its positions in the region continued to come under heavy bombardment, including shellfire allegedly from across the porous border with former Soviet master Russia.
Government forces have made major gains over the past month and said they are getting close to cutting off fighters in Donetsk from the Russian border and their comrades in Lugansk.
Kiev has promised to stamp out the insurgency in the near future but analysts warn the fighting could drag on as rebels have holed up in major cities and pledged to fight to death.
A top rebel chief admitted that Donetsk was in a state of "siege" and said fighters were trying to battle past a government blockade.
"Our guys are dying heroically in efforts to break through," said deputy prime minister of the self-styled Donetsk People's republic Vladimir Antyufeev.
It is the civilians in the blighted region who are bearing the brunt of the violence.
In the face of the punishing government blockade, the mayor of Lugansk, a city of some 420,000, is warning of a looming "humanitarian catastrophe" as electricity has failed and water and fuel supplies have run out.
The United Nations says more than 100,000 people have fled the fighting for other parts of Ukraine, while Russia claims another half a million have crossed the border in search of refuge.