UK Prime Minister Sir Keir Starmer will host Volodymyr Zelensky in Downing Street later on Sunday, joined by French President Emmanuel Macron and German Chancellor Friedrich Merz, to discuss European support for Ukraine.

Before the meeting, Kyiv officials reported that a Russian drone struck a storage facility for spent nuclear fuel near the Chornobyl nuclear plant in northern Ukraine.

They confirmed a fire was extinguished with no injuries and radiation levels stayed stable. Zelensky described the incident as a deliberate and "vile Russian strike".

In a separate event, authorities said at least three people died in a Russian strike on a village outside Zaporizhzhia in the southeast.

Zaporizhzhia has endured repeated Russian attacks recently, with at least two fatalities there on Saturday.

Ukraine's state nuclear operator Enerhoatom said the Russian strike on Chornobyl "partially destroyed" a spent nuclear fuel storage building.

The operator reported no injuries, a contained fire, and normal radiation levels.

Enerhoatom condemned Moscow for deliberately threatening nuclear safety, a view echoed by Zelensky.

"Russia deliberately struck this particular nuclear infrastructure facility," Zelensky posted on X, calling the building "an extremely critical infrastructure facility" and the attack "vile".

He detailed Russian overnight strikes across 13 regions and noted Moscow had launched 88 missiles, more than 3,250 drones and 1,800 guided bombs over the past week.

On Saturday, Ukraine struck St Petersburg and surrounding areas during the final day of a major economic forum, an attack Russian authorities called "unprecedented".

Days earlier, Kyiv hit the outskirts of the same city, about 1,000km from Ukraine, as Russian President Vladimir Putin's flagship forum began, sending a large plume of black smoke over the skyline.

In the four years since Moscow's invasion started, Ukraine has strengthened its defence sector and can now regularly target sites inside Russia.

The three Western powers at Downing Street, known as the E3 group, count among Kyiv's strongest allies. The UK and France lead the "coalition of the willing" to provide security guarantees for Ukraine in any future peace process.

The group last met in London in December when the US pressed Moscow and Kyiv to agree quickly on ending the war.

Since then US mediation efforts for a truce have faded and Washington's attention has turned to the Iran conflict.

On Friday, Putin rejected Zelensky's proposal for face-to-face talks on ending the war, saying he saw no point in meeting the Ukrainian leader.

Zelensky sent an open letter calling for direct negotiations and wrote that it would be "wrong to simply wait" for the conflict to regain US attention.

Speaking at the economic forum on Friday, Putin refused the meeting request and repeated that a truce would only let Ukraine regroup.

He said he would end the war only when Russia's goals had been met.