Russian authorities say Ukraine has launched an "unprecedented attack" on and around St Petersburg, as the city hosts the final day of Russia's annual economic forum.
More than 140 drones were shot down over the surrounding Leningrad region, governor Aleksandr Drozdenko said, while the city's governor, Alexander Beglov, urged residents to remain indoors for the first time since the beginning of the war.
Ukraine's president said his forces hit Russia's arsenals and a naval base in what he called a just response to Russian attacks.
It comes just a day after Russia's president delivered a speech at the forum, in which he said there was no point in meeting Zelensky, who had called for direct talks on ending the war.
Ukrainian President Volodymyr Zelesnky posted on social media on Saturday to say it was "time to end this war", but accused Putin of wanting to "keep fighting".
He said his country's drones had covered a distance of 1,000km (620 miles) to the St Petersburg region, targeting "the enemy navy's arsenals and a base in Kronstadt".
An oil depot in the Krasnodar region of southern Russia - 500km (310 miles) away - had also been hit, he added.
This follows an open letter sent on Thursday by Zelensky calling for face-to-face negotiations with Vladimir Putin to end the war, which began with Russia's full-scale invasion in 2022.
He wrote that it would be "wrong to simply wait" for the conflict to once again come to the attention of the US.
On Friday, Putin refused the request for a meeting, reiterating his position that peace talks should precede any ceasefire.
He said he would only end the war when Russia's goals had been met.
Russia's longstanding position is that Ukraine should withdraw from the Donetsk, Luhansk, Kherson and Zaporizhzhia regions, as well as abandon efforts to join Nato.
Meanwhile, in the Russian-occupied Luhansk region of eastern Ukraine, the Moscow-installed authorities have suspended coach services on two motorways following a campaign of Ukrainian drone strikes targeting Russian logistics.
They urged local residents not to use them "for security reasons".
The Russia-backed administration also banned commuter train services and transportation of groups of children within Luhansk.
Putin had said Russia was in full control of the so-called "Luhansk People's Republic".
In recent weeks, Ukraine's drone forces have been targeting Russian logistics in occupied parts of Ukraine.
An analyst told the BBC that more than 200 lorries and over 30 fuel trucks had been hit since the beginning of May.
