Ukraine’s President Volodymyr Zelensky vowed that the attack “will not go unanswered” after photos posted by local authorities showed the burnt-out metal shell of the vehicles, with bodies and debris strewn across the road.
“Russia is trying to destroy all life in (the) Donbas (region) and the world must respond to this,” he wrote on Telegram, warning that the death toll could rise.
Police said the buses were hit with a glide bomb. Three more people were killed in a nearby village as a result of shelling, the emergency services said.
The strikes come just a day after five children were among 22 killed when a Russian missile flattened a five-storey apartment block in Pryluky, in the northern Chernigiv region.
“The Russians are deliberately targeting civilians,” Donetsk Governor Vadym Filashkin said, accusing Moscow of flouting “every conceivable rule of warfare and norm of international humanitarian law”.
Kramatorsk City Council called it “yet another horrific crime committed by the Russian army against the civilian population”.
“Once again, the Russians have struck a location where there are absolutely no military targets,” it added.
There has been mounting concern about the increase in civilian deaths and injuries in the nearly five-year conflict, as both sides step up long-range attacks beyond their borders.
Since Russia’s full-scale invasion in February 2022, Ukraine has accused its forces of deliberately attacking and killing civilians.
The United Nations has verified more than 17,000 civilian deaths throughout the war but says the real number is considerably higher.
Last week, Zelensky said his Russian counterpart Vladimir Putin had sanctioned massive attacks on civilian areas, a claim the Kremlin denies.
But touring the site of the Pryluky attack on Thursday, visiting UK foreign minister Ed Miliband said there was “no clearer sign of Putin’s evil, evil intent and strategy in this conflict”.
“Putin once said that he was going to win on the battlefield,” he told reporters, as London announced more sanctions on Moscow. “He is trying to win by terrorising civilians.”
Zelensky urged the United States to “raise the pressure” on Russia, including through providing better air defence systems, to force Putin to the negotiating table.
