Russia has launched a major aerial bombardment against Ukrainian infrastructure targets as talks between the US and Ukraine in Florida are set to enter a third day.

Overnight Russia launched 653 drones and 51 missiles, most of which were downed, authorities said. One strike hit a railway hub at the town of Fastiv outside Kyiv, destroying the main station building and damaging rolling stock.

President Volodymyr Zelensky said the attack had been “meaningless from a military point of view, and the Russians could not have been unaware of this”.

Earlier US and Ukrainian negotiators urged Russia to show a “serious commitment to long-term peace” after talks in Moscow failed to produce a breakthrough.

Moscow has intensified attacks on Ukraine’s energy sector and infrastructure in recent weeks.

On Saturday Ukraine’s energy ministry said Russian attacks had hit energy facilities in eight regions, causing blackouts.

Meanwhile the UN’s nuclear watchdog said the Zaporizhzhia nuclear power plant temporarily lost all external power overnight – the 11th time this has happened since Russia’s full-scale invasion of its neighbour.

The Russian defence ministry said it had launched a “massive strike” in response to what it called Ukrainian attacks on civilian targets.

“Russia continues to disregard any peace efforts and instead strikes critical civilian infrastructure,” Ukrainian Foreign Minister Andrii Sybiha said.

“This shows that no decisions to strengthen Ukraine and raise pressure on Russia can be delayed. And especially not under the pretext of peace process,” he added.

In Florida, a statement posted by US special envoy Steve Witkoff said two days of talks with Rustem Umerov, secretary of Ukraine’s national security council, had been “constructive”.

Witkoff and Umerov “agreed on the framework of security arrangements” that could such an agreement and “discussed necessary deterrence capabilities to sustain a lasting peace”, their statement said without giving details.

The prospect of ending the war depended on Russia’s readiness to take “steps towards de-escalation and cessation of killing”, the statement added.

The negotiations, which are also attended by US President Donald Trump’s son-in-law Jared Kushner, will continue for a third day on Saturday.

The Florida talks saw Ukraine’s team briefed on a recent meeting between Witkoff, Trump’s most senior overseas envoy, and Russian President Vladimir Putin.

Witkoff spent almost five hours with Putin in Moscow on Tuesday, after which the Kremlin said “no compromise” had been reached on a draft US peace plan.

The Kremlin said Putin was ready to continue meeting the Americans “as many times as needed”, but Ukraine and its allies in Europe have called into question the Russian leader’s commitment to ending the war.

On Friday, Ukrainian President Volodymyr Zelensky said he wanted to “obtain full information about what was said in Moscow and what other pretexts Putin has come up with to drag out the war”.

Kyiv pushed for revisions to the initial US peace plan, which was widely seen as favourable to Moscow when an initial version leaked to the media. An updated version has not been shared publicly.

Major points of contention remain between the two sides, including security guarantees for Ukraine post-war and territorial concessions.

Russia currently controls roughly one-fifth of Ukraine’s territory, including swathes of the Donbas area in the east – made up of the Donetsk and Luhansk regions.

In an interview with India Today on Friday, Putin warned Ukrainian troops to withdraw fully from the region this week, saying Russia would otherwise “liberate these [Donbas] territories by force”.

Kyiv and its European allies believe the most effective way to deter Russia from attacking again in the future would be to grant Ukraine membership of Nato, or to provide comprehensive security guarantees.

Russia is staunchly opposed, while Trump too has repeatedly signalled he has no intention of letting Ukraine join the military alliance.

The prospect of Ukraine joining Nato was a “key question” that was tackled in Moscow, the Kremlin said on Wednesday.

Trump said those talks were “reasonably good”, but it was too soon to say what would happen as “it does take two to tango”.