The overnight strikes reduced part of a nine-storey apartment block in Kyiv's western suburbs to rubble and wounded more than a hundred in the capital, according to authorities.

The Russian army meanwhile claimed to have captured Chasiv Yar, a strategically important hillside town in eastern Ukraine where the two sides have been fiercely fighting for months.

Moscow has stepped up its deadly aerial assaults on Ukraine in recent months, resisting US pressure to end its nearly three-and-a-half year invasion as its forces grind forward on the battlefield.

Speaking virtually to a conference marking 50 years since the signing of the Cold War-era Helsinki Accords, Zelensky said he believed Russia could be "pushed" to stop the war.

"But if the world doesn't aim to change the regime in Russia, that means even after the war ends, Moscow will still try to destabilise neighbouring countries," the Ukrainian leader added.

Between late Wednesday and early Thursday, Russia fired over 300 drones and eight cruise missiles at Ukraine, the main target of which was Kyiv, the Ukrainian air force said.

One missile tore through a nine-storey residential building in western Kyiv, tearing off its facade, authorities said.

AFP journalists at the scene of the strike saw rescuers scouring through a smouldering mound of broken concrete, the belongings of residents scattered among the debris.

"It's a shock. I still can't get my bearings. It's very frightening," Valentyna Chestopal, a 28-year-old resident of Kyiv, told AFP.

Tymofii was woken up by the sound of a missile, "everything started falling on me. It was terrifying," said the resident of the Solomyansky district, whose apartment was destroyed and described the experience as "a nightmare."

Among the victims was a six-year-old boy, who died on the way to hospital in an ambulance, the head of the city's military administration, Tymur Tkachenko, said in a post on Telegram.

The Russian army said it had hit Ukraine's military airfield, ammunition warehouse and drone production facilities with a combined overnight strike using high-precision weaponry and drones.

The attack came just days after US President Donald Trump issued a 10-day ultimatum for Moscow to halt its invasion, now in its fourth year, or face sanctions.

- Key capture in east -

Russia said on Thursday it had captured the town of Chasiv Yar, which had been a strategically important military hub for Ukrainian forces in the eastern Donetsk region.

The town "was liberated by Russian forces", Russia's defence ministry said in a statement, while a Ukrainian army spokesperson rejected Russia's claim as "lies".

Ukrainian military analyst Oleksandr Kovalenko said the Russians "have full control over the entire northern and eastern part," of Chasiv Yar including districts that were hardest to get.

But that the fighting for the western side was still ongoing, added.

He said the situation was "very difficult" in the town that has been holding up in urban skirmishes for over two years, a record time in the war.

Taking control of Chasiv Yar would represent a major military boon for Russia, which has been making incremental but steady territorial gains for months.

Home to around 12,000 people before the war but now largely destroyed, the town's capture would pave the way for Russian forces to advance on remaining civilian strongholds in the eastern Donetsk region.

These include the garrison city of Kramatorsk and Sloviansk, important logistical bases for the Ukrainian military and home to many civilians, who have up to now not fled the fighting.

The Kremlin has made the capture of the Donetsk region a priority since it claimed the industrial region as part of Russia in September 2022.

Russia, which denies targeting civilians, has not yet commented on the strike or Zelensky's call for regime change.

Putin has himself called for Zelensky to be removed from office and has repeatedly questioned his legitimacy.

- Anti-corruption bill -

Thursday's attacks came just hours before lawmakers in Ukraine's parliament voted to overturn a highly criticised law that curbed the powers of two anti-graft bodies.

Zelensky, who signed the new bill into law shortly after the vote on Thursday, reversed course after the legislation sparked the biggest public unrest in Ukraine since Russia's invasion began.

The original law had put the National Anti-Corruption Bureau of Ukraine (NABU) and Specialised Anti-Corruption Prosecutor's Office (SAPO) under the direct authority of the prosecutor general, who is appointed by the president.

Critics said the move would allow Zelensky to meddle in high-profile corruption cases, while the European Union warned the bill could derail anti-corruption reforms key to joining the bloc.

A total of 331 members of parliament, the minimum required being 226, approved the new legislation, which was lauded by the European Union as a key safeguard against corruption.