KIEV, Aug. 3 - Ukraine on Monday reported the death of four soldiers in clashes with pro-Russian rebels that came just hours before another failed bid to negotiate an end to the 15-month separatist revolt.

Military spokesman Andriy Lysenko said another 15 servicemen had been wounded in the past 24 hours of fighting across the eastern Russian-speaking provinces of Lugansk and Donetsk, AFP reported.

"The first week of August... has been very tense," Lysenko told reporters.

The insurgents countered that indiscriminate shelling by Kiev's forces had damaged power lines and four buildings in Horlivka - a rebel bastion more than 20 miles northeast of their de-facto capital Donetsk.

The local village council said it was checking whether any civilians were killed in the reported attack.

The incessant exchanges of fire and mutual accusations of responsibility have frustrated Western efforts to resolve Europe's bloodiest and most protracted conflict since the Balkans crises of the 1990s.

The warring sides and Russia on Monday launched another round of European-mediated negotiations in the Belarussian capital Minsk that seek to salvage a sweeping but largely ineffective ceasefire and political reconciliation agreement signed nearly six months ago.

The latest meetings were meant to agree the withdrawal of smaller weapons from a proposed 30-kilometre-wide (18-mile) buffer zone that splits rebel-run districts from the rest of Ukraine.

Donetsk separatist negotiator Denis Pushilin said the discussions were "aborted by the Ukrainian side" after more than six hours because of Kiev's refusal to move back its forces from four strategic locations.

Pushilin added that some talks would continue into Tuesday.

"But most likely, nothing will get done," he said. Kiev and Moscow envoys did not speak to reporters in Minsk.

President Petro Poroshenko and his foreign allies believe that Russian President Vladimir Putin does not necessarily want to annex the two rebellious regions in the same way he seized the Black Sea peninsula of Crimea in March 2014.

But they do think the Kremlin is trying to keep Kiev politically off-balance and forced to finance a military operation it can ill afford.

Some analysts believe that the situation is being mitigated somewhat by enduring diplomatic efforts to avert a "frozen conflict" that keeps the EU's eastern frontier on security alert for decades to come. (afp/ez)