The death toll rose from an initially reported 22 after three more bodies were retrieved from the rubble in the town of Chaplyne as rescue operations there ended, Ukrainian presidential aide Kyrylo Tymoshenko said on Thursday.
The Vyshgorod region, directly north of Kyiv, also came under rocket attack, but there were no casualties reported, regional official Olexiy Kuleba said on the Telegram channel.
The missile strikes and artillery shelling of frontline towns, such as Kharkiv, Mykolaiv, Nikopol and Dnipro, followed President Volodymyr Zelenskiy's warnings of the risk of "repugnant Russian provocations" ahead of Wednesday's 31st anniversary of independence from Moscow-dominated Soviet rule.
August 24 also coincided with six months since Russian forces invaded Ukraine, touching off Europe's most devastating conflict since World War II.
As rescue operations wrapped up in Chaplyne, residents of this small town, located some 145km west of Russian-occupied Donetsk, grieved for their loved ones amid the rubble of their wrecked homes.
Local resident Sergiy lost his 11-year-old son in the strike. "We looked for him there in the ruins, and he was lying here. Nobody knew that he was here. Nobody knew," he said as he crouched next to his covered body.
The Russian defence ministry had no immediate comment on the attack. Speaking in Uzbekistan, Defence Minister Sergei Shoigu repeated Moscow's line it had deliberately slowed what it calls a "special military operation" in Ukraine to avoid civilian casualties.
Russia denies targeting civilians. It has also said that rail infrastructure is a legitimate target since it serves to supply Ukraine with Western weapons.
US Secretary of State Antony Blinken condemned the strikes.
"Russia's missile strike on a train station full of civilians in Ukraine fits a pattern of atrocities," he wrote on Twitter.
"We will continue, together with partners from around the world, to stand with Ukraine and seek accountability for Russian officials."
Wednesday's public holiday celebrations were cancelled but many Ukrainians marked the occasion by wearing embroidered shirts typical of the national dress.
Ukraine declared independence from the disintegrating Soviet Union in August 1991, and its population voted overwhelmingly for independence in a referendum that December.
Air raid sirens blared at least seven times in Kyiv during the day, though there were no attacks. Ukrainian authorities said air raid alerts were sounded 189 times across the country on Wednesday, more than at any other time during the six-month conflict.
Zelenskiy and his wife, Olena, joined religious leaders for a service in Kyiv's 11th-century St Sophia cathedral and laid flowers at a memorial to fallen soldiers.
The 44-year-old leader said Ukraine would recapture Russian-occupied areas of eastern Ukraine and the Crimean peninsula, which Russia annexed in 2014.
Ukrainian forces shot down a Russian drone in the Vinnytsia region while Russian missiles landed in the Khmelnytskyi area, regional authorities said, both west of Kyiv and hundreds of kilometres from front lines. No damage or casualties were reported.
