DONETSK, Ukraine -- Separatist rebels on Monday attacked a caravan of cars carrying refugees trying to flee war-ravaged eastern Ukraine, killing "dozens" of people in a devastating barrage of artillery fire, Ukrainian military officials said, although rebel leaders denied there had been any attack at all.
Col. Andriy Lysenko, a spokesman for the Ukrainian military, said in Kiev, the capital, that "terrorists had perpetrated a bloody crime" by attacking the refugee convoy with Grad rocket systems and other heavy weapons supplied by Russia.
Although Lysenko did not give a precise tally of the fatalities, if confirmed, the attack would rank among the most deadly for civilians since separatist militants began seizing cities and towns in the region more than four months ago.
"Many people died, including women and children," he said, adding that the assault took place on the main southern highway leading out of the regional capital of Luhansk, between the villages of Khryashchuvatye and Novosvitlivka.
Oleksiy Dmytrashkivsky, a spokesman for the Ukrainian government's military operation in the east, later said that 15 bodies had been recovered from the smoldering vehicles and that servicemen were collecting the body parts of at least 10 more people.
The highway where Ukraine says the attack took place connects Luhansk, which has been the focus of a government offensive to regain control of territory controlled by separatists, with the Russian border. The road has seen heavy fighting in recent days as Ukrainian forces have tried to seal off supply routes into the city from Russia that are used by militants to replenish their supply of weaponry and fighters.
In Donetsk, the last major rebel stronghold, Alexander Zakharchenko, the prime minister of the self-declared Donetsk People's Republic, denied the event had occurred.
"Not one column of refugees was fired on in Luhansk at that time," Zakharchenko said.
"The Donetsk People's Republic and Luhansk People's Republic did not shoot at refugees with Grad supposedly provided by Russia," he said.
All Grad rocket launchers in Luhansk, he said, were captured as "trophy" weapons from the Ukrainian army, not provided by Russia. About the refugee convoy, he added, "we would not form a column ourselves and then shoot at it ourselves."
Zakharchenko then countered with his own allegation of war crimes.
The Ukrainian army, he said, had used a chemical weapon in combat in eastern Ukraine, although its exact nature was unclear. Pro-Russia soldiers operating in a village where cluster munitions had fallen developed rashes and be
Zakharchenko's claim could not be immediately verified.
There was no independent confirmation of the Ukrainian government's report, which came after repeated rebel accusations that Ukraine is responsible for an increasing number of civilian casualties in the combat zone. The U.S. State Department condemned the attack but said it was unable to confirm who was responsible.
Russia has accused Ukraine of stepping up its operations in the area to wreck what Moscow describes as a humanitarian mission involving a convoy of about 270 trucks carrying relief supplies. The trucks have been stalled for days on the Russian side of the border.
The report of civilian deaths provided a grim backdrop as diplomatic efforts to resolve the Ukraine crisis failed to progress Monday during talks in Berlin.
Information for this article was contributed by Andrew Roth and Melissa Eddy of The New York Times and by Nataliya Vasilyeva, Peter Leonard, Yuras Karmanau, Juergen Baetz, Matt Lee, Jim Heintz and Lynn Berry of The Associated Press.
A Section on 08/19/2014