Ukrainian and Russian officials have blamed each other for the sharp escalation in violence that has occurred in recent days along the front line in eastern Ukraine.
Russian President Vladimir Putin pinned the upsurge on alleged preparations by Kyiv to retake territory it has lost to Russian-backed separatist forces since fighting broke out in February 2014.
"Unfortunately, we are now witnessing an escalation whose blame lies not on the rebels but on their foes," Putin said on August 18 during a visit to Crimea.
He added that he hopes the situation "will not lead to large-scale violence."
Ukrainian military spokesman Vladyslav Seleznyov accused "Russia of trying to pile additional pressure on Ukraine."
He said the increased shelling and other attacks by the separatists "proves that the [rebels] are not looking for a peaceful way out of this conflict."
Ukraine said on August 18 that one soldier had been killed and another wounded in fighting in the previous 24 hours.
That report came one day after at least nine were killed on both sides in eastern Ukraine during some of the fiercest attacks since a cease-fire agreement was signed in February in Minsk.
But Seleznyov said on August 18 that there had been a "sharp drop-off in the number of provocative attacks on Ukrainian positions" in the past day compared to the last week of attacks.
The rebels have been fighting to seize control of a road linking their de facto capital, Donetsk, with Mariupol, a southeastern port held by the government where much of the industrial region's factory output is exported from.
"There can be no mistake as to who is responsible -- Russia and the separatists are launching these attacks, just as they escalated the conflict last August," U.S. State Department spokesman John Kirby said on August 17.
The Russian Foreign Ministry denounced Kirby's comments as "the U.S. State Department's effective approval of the Ukrainian Army's attacks on rebel positions."
At least 6,400 people have been killed in the fighting in eastern Ukraine in the past 16 months and an estimated 1.4 million people driven from their homes.
With reporting by AFP, TASS, and Interfax