Russian forces on Wednesday launched a rocket attack on a Ukrainian train station on the country’s Independence Day, killing 25 people.
Rockets hit five passenger rail cars of a train in the small town of Chaplyne, about 145 kilometres west of Russian-occupied Donetsk in eastern Ukraine, President Volodymyr Zelenskyy said in a video address to the UN Security Council, Reuters reported.
"Chaplyne is our pain today," he said in a later evening video address.
Ukraine would hold Russia responsible for everything it had done, he said.
The death toll has risen to 25 from 22, including an 11-year-old boy found under the rubble of a house and a 6-year-old killed in a car fire near a train station that took a hit, the deputy head of the Ukrainian presidential office, Kyrylo Tymoshenko, said on Thursday, AP reported.
A total of 31 people sustained injuries, he said.
Earlier, Mr Zelenskyy had put the number of wounded at about 50.
Mr Zelenskyy had warned of the risk of "repugnant Russian provocations" before the 31st anniversary on Wednesday of Ukraine's independence from Moscow-dominated Soviet rule, and public celebrations were cancelled.
The holiday also coincided with six months since Russian forces invaded Ukraine, touching off Europe's most devastating conflict since the Second World War, Reuters reported.
Mr Zelenskyy's aide Kyrylo Tymoshenko later said Russian forces had shelled Chaplyne twice.
A boy was killed in the first attack when a missile hit his house, and 21 people died later when rockets hit the railway station and set fire to five train carriages, he said.
The Russian defence ministry did not immediately respond to a request for comment. Russia denies aiming at civilians.
"Russia’s missile strike on a train station full of civilians in Ukraine fits a pattern of atrocities," US Secretary of State Antony Blinken said on Twitter. "We will continue, together with partners from around the world, to stand with Ukraine and seek accountability for Russian officials."
On Ukraine's holiday, Russia's military avoided Kyiv and aimed at front-line towns like Kharkiv, Mykolaiv, Nikopol and Dnipro with artillery attacks, Ukraine presidential adviser Oleksiy Arestovych said.
"Massive shelling of Ukraine on Independence Day," fellow presidential adviser Mykhailo Podolyak added on Twitter.