Death toll in Independence Day attack on rail station in Ukraine rises to 25

The death toll from a Russian rocket attack as Ukraine observed its Independence Day has risen to 25, including an 11-year-old boy found under the rubble of a house and a six-year-old killed in a car fire near a train station that was hit.

The deputy head of the Ukrainian presidential office, Kyrylo Tymoshenko, said a total of 31 people sustained injuries.

The lethal attack took place in Chaplyne, a town of about 3,500 people in the central Dnipropetrovsk region.

• Six months since Russia invaded Ukraine: War to last much longer than expected, Ukrainian MP says
• Former Army chief: Russians made 'every possible military mistake'
• Ukraine: How social media and trolling has became a factor in conflict

It comes after Ukrainian President Volodymyr Zelensky had warned for days that Moscow might attempt "something particularly cruel" this week – the latest significant attack taking place on the embattled country's Independence Day.

"Chaplyne is our pain today," Mr Zelensky said in his nightly video address to the nation, following the attack which reportedly hit five passenger rail carriages.

Ukraine had been bracing for especially heavy attacks surrounding the national holiday that commemorates Ukraine's declaration of independence from the Soviet Union in 1991.

Ukraine also marked the six-month point in the war.

Ahead of Independence Day, Kyiv authorities banned large gatherings in the capital through until Thursday for fear of missile strikes.

Outgoing British Prime Minister Boris Johnson marked the holiday with a visit to Kyiv – his third since the war broke out.

Other European leaders used the occasion to pledge unwavering support for Ukraine, which is locked in a battle that was widely expected to be a lightning conquest by Moscow but has turned into a grinding war of attrition.

Watch: Russian military has 'failed spectacularly'.

Russian defence minister Sergei Shoigu, speaking on Wednesday at a meeting of his counterparts from a security organisation dominated by Russia and China, claimed the slow pace of Moscow's military action was due to what he said was an effort to spare civilians.

Russian forces have repeatedly targeted civilian areas in cities, including hospitals and a Mariupol theatre where hundreds of people were taking shelter.

But Mr Shoigu said Russia is carrying out strikes with precision weapons against Ukrainian military targets, and "everything is done to avoid civilian casualties".

"Undoubtedly, it slows down the pace of the offensive, but we do it deliberately," he said.

He also criticised the US and its allies for "continuing to pump weapons into Ukraine", saying the aid is dragging out the conflict and increasing casualties.