Two teenage boys were killed while playing football at a Donetsk school on Wednesday, when a mortar shell reportedly hit their sports field in the Kuibyshevskiy district less than three miles from where fierce clashes are raging at the city's airport.
Four others were injured in the attack, which underscores the near total collapse of a fragile peace deal in the wake of a rebel-held election in the region on Sunday.
According to the latest report from the United Nations, at least 300 people have been killed in fighting since a supposed ceasefire came into effect on September 5 and a total of at least 3,660 people have died in the conflict since fighting broke out in mid-April.
Both of the warring sides are blaming each other for the breakdown of the Minsk truce.
While the rebels' leaders, inaugurated in a ceremony on Tuesday, claim the vote was held with the aim of legitimizing their authority to open negotiations, Kiev has slammed the election as an "illegitimate farce" and a violation of a component of the peace deal which provided for local elections to be held across Ukraine on December 3.
The controversial poll has also attracted widespread criticism in the West where authorities fear the vote, recognized by top Russian officials, is part of a bid to create a frozen conflict in the region along the lines of those surrounding the breakaway republics of South Ossetia and Abkhazia in Georgia, and of Transnistria in Moldova. In both cases, the protracted stalemates have prevented the former Soviet satellites from progressing towards NATO.
In response to the rebel election, Ukrainian Prime Minister Arseniy Yatsenyuk has said that $2.6 billion in state subsidies allotted to the regions of Donetsk and Luhansk will be held back until "(those) terrorists clear out of there."
Most pensions and social benefits have already been cut off for more than four months, leaving many elderly and poor people desperately trying to carve out existence in an area where war has devastated infrastructure and further depressed an already beleaguered economy.
"The money we pay into those territories today does not get to the people but is stolen by Russian bandits, and this would be nothing but directly supporting Russian terrorism," the prime minister said in a justification of the move.
The government has said that locals will receive back-payments when the breakaway territories are back under Ukraine's control and emphasized that Kiev will not cut off gas and electricity to the region over the cold winter months.
"Those are our citizens and the government will not allow these people to freeze, as this would lead to a humanitarian catastrophe," Yatsenyuk added.
Hostilities show no sign of abating at present, however. According to NATO, Russian troops are again edging closer to Ukraine's border, with seven battalions now stationed near the frontier. "We believe that this was probably to bring some pressure on (Ukraine) and make sure that the elections went according to the separatists' plans," NATO General Phillip Breedlove said during a Pentagon briefing.
Ukraine has claimed that thousands of Russian soldiers have been fighting alongside the rebels in the country's east, but General Breedlove said the current number is more likely around 250 to 300. The general noted, however, that the intruding military were "not fighting formations... (but) ... specialists who are in there doing training and equipping of the separatist forces."
While the rebels' frontline with Ukrainian forces appears to be "hardening" and "becoming more like a border between two states," Breedlove added, "the Ukraine-Russia border is wide open... It is completely porous. Russian equipment, resupply, training flows back and forth freely".
Moscow has denied sending men and weapons to support the rebels despite what the West has called overwhelming evidence to the contrary.
Russia is also flexing its military might further afield. According to NATO Secretary General Jens Stoltenberg the number of Russian aircraft intruding into airspace above the Atlantic Sea, Baltic Sea and Black Sea has risen dramatically. "The numbers of (plane) intercepts have so far this year been over 100, which is about three times as much as the total number of intercepts the whole of last year," Stoltenberg told reporters at a press conference earlier this week.
On the other side of the fence, Ukrainian forces are hunkering down for the long cold winter ahead. Following a meeting with security chiefs in the wake of the controversial polls, Ukrainian President Petro Poroshenko announced on Wednesday that he would be sending hundreds more troops to reinforce frontline areas including Mariupol, Kharkiv and north Luhansk.
Keeping up morale in the bitter cold will be tough, however. Along the western frontline, weary looking soldiers and battalion fighters are manning checkpoints in trench coats, while their comrades make tea and food over camp fires amid tents and frozen lines of washing.
Talking to VICE News at one of the region's many road blocks, Yaroslav, a young conscript soldier from Kiev, grumbled about the conditions. "It's fine for those terrorists they can go home and have a shower and see their wives and kids," he said gesturing in the direction of a rebel checkpoint just a few miles down the road. "I've not seen my family since since July, even Stalin rotated his troops more often than this".
Follow Harriet Salem on Twitter: @HarrietSalem