The death toll from a Russian strike on a train station in central Ukraine rose to 25 overnight, the state rail operator said on Thursday.

The strike targeted a station in the city of Chaplyne in the region of Dnipropetrovsk, on Wednesday.

"As of this morning, we have 25 dead, including two children, and 31 people injured, including two children," Ukrainian Railways said on Telegram on Thursday.

Ukrainian President Volodymyr Zelensky first announced the strike in the evening on Wednesday -- as the nation marked the grim milestone of six months of war, and its annual Independence Day.

"Chaplyne is our pain today," Zelensky said.

Since the war started in February, Ukraine's railways have been vital in the effort to evacuate vast swathes of the country.

In April, a rocket attack on a station in the eastern city of Kramatorsk killed at least 57 civilians as they waited on the platform to be transported west to safety.

As the war enters its seventh month most of the fighting between Russia and Ukraine is taking place in the south and east, with neither side conceding much territory.

Nonetheless Kyiv accuses Moscow of regularly striking Ukrainian cities with long-range missiles.