Russian strikes kill 21 in east Ukraine: governor
"At least 10 killed and 15 wounded, the consequences of the shelling of the Avdiivka coke plant by the Russian occupiers," the governor Pavlo Kyrylenko said on Telegram.
The coke plant - one of Europe's largest - has been the target of multiple attacks in recent years as Russia-backed separatist forces battled Ukrainian troops.
Later Tuesday, Kyrylenko said five more people were killed in shelling in the town of Lyman, four in the town of Vugledar and one each in the villages of Velyka Novosilka and Shandrygolove each.
Kyrylenko said this was the highest death toll since a Russian strike on a train station in the city of Kramatorsk killed 59 people about a month ago.
"For every crime committed on our land, the Russians will be punished," he said.
Kyrylenko said the strike in Avdiivka came as "the workers had just finished their shift and were waiting at the bus stop for a bus to take them home from the factory."
"The Russians knew where they were aiming."
Avdiivka - an industrial town north of separatist-controlled Donetsk - is on the frontline of the war with Russia.
Russia has in recent weeks increased attacks on territories held by Kyiv in the eastern Donbas region, now the focus of its invasion of Ukraine.
Coke is a fuel with a high carbon content and is an important industrial product, used mainly in iron ore smelting, but it can also be used as a fuel in stoves and forges.