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 war began.
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 a day after Vladimir Putin told the forum there was no point in meeting Volodymyr Zelensky, who had called for direct talks on ending the war.
Zelesnky posted on social media on Saturday to say it was "time to end this war", but accused Russia's leader 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", referring to the main outpost of the Russian Navy's Baltic Fleet.
Drozdenko said Ukraine's attacks caused a fire at an unspecified military facility, and that residents were being evacuated. He also said buildings sustained "insignificant" damage.
According to Zelensky, an oil depot 500km (310 miles) away, in the southern Krasnodar region, was also hit as part of Ukraine's "long-range sanctions" - a euphemism for strikes on Russia.
These latest attacks follow Ukrainian strikes on the outskirts of St Petersburg as Putin's flagship economic forum was getting under way just days earlier.
The major forum, designed to attract foreign investment into the country, drew thousands of guests from 130 countries, including a low-key US delegation.
On Thursday, Zelensky called for a ceasefire and face-to-face negotiations with Putin to end the war, which began with Russia's full-scale invasion in 2022.
He wrote in an open letter that it would be "wrong to simply wait" for the conflict to once again come to the attention of the US.
Speaking at the economic forum on Friday, Putin refused the request for a meeting and reiterated his position that a truce would only allow Ukraine to regroup.
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.
Ukraine has refused to give up any territory, arguing that concessions to Moscow would embolden it to invade again in the future.
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.
In the four years since Russia's invasion began, Ukraine has developed its defence sector.
Kyiv is now able to regularly hit targets within Russia, focusing its efforts on energy infrastructure and oil facilities, which it sees as fuelling Moscow's war machine.
