Fierce fighting between government forces and pro-Russian rebels left dozens of civilians dead with artillery pounding central Donetsk yesterday as Ukrainian troops pushed on with a bloody offensive.
Deadly battles to crush the ailing rebellion appeared to intensify ahead of a fresh round of diplomacy that will see the presidents of Russia and Ukraine meet next week for the first time in months.
Clashes in and around the besieged main rebel stronghold of Donetsk killed 43 civilians in the past 24 hours, local authorities said.
AFP journalists saw fierce mortar fire tear through the centre of the city close to the state-of-the-art stadium of football team Shakhtar Donetsk, as Ukrainian troops tightened the vice on insurgents holed up in the mining hub.
Street battles were raging in Ilovaysk, a key railway hub some 45 kilometres east of Donetsk, with authorities saying nine soldiers died in the area in the last 24 hours, including a US national who fought for a Ukrainian volunteer battalion.
The renewed offensive comes as Ukrainian President Petro Poroshenko gears up for a meeting in Minsk with Russia's Vladimir Putin, the heads of Belarus and Kazakhstan, and EU officials next week.
Kiev has accused Moscow of ratcheting up arms flows to help bolster the separatists as Ukrainian forces have pushed deeper into dwindling rebel territory with clashes killing around 2,200 people since April.
Western powers also fear Putin could be preparing to send in the 20,000 troops Nato says he has massed on the border as a last roll of the dice.
A Ukrainian military spokesman could not confirm claims from a commander in the field that a massive convoy of Russian armoured vehicles had entered the second-largest insurgent city of Lugansk.
Meanwhile, there seemed to be some signs of progress in the week-long saga that has seen some 300 Russian lorries with humanitarian aid parked up at the border with Ukriane's Lugansk region.
Kiev fears that the convoy may be attacked if allowed to cross into rebel territory and could give the Kremlin a pretext to invade.
Russia said on Wednesday that it had agreed with the International Committee of the Red Cross (ICRC) to "begin movement" of the convoy despite worries over safety guarantees.