Russia has carried out a new massive overnight drone attack on Ukraine's capital Kyiv, killing at least one person, local officials have said, reports BBC.
Kyiv's mayor Vitaliy Klitschko said a man died when drone wreckage fell near a petrol station. A woman was injured.
Overall, Russia launched a record 54 so-called kamikaze drones on Ukrainian targets, 52 of which were shot down, Ukraine's Air Force reported.
In Kyiv alone, more than 40 drones were downed, officials said.
This information has not been independently verified.
Russia - which launched its full-scale invasion in February 2022 - has in recent weeks stepped up its attacks on Kyiv, seeking to overwhelm the capital's defences.
Earlier on Sunday, air raid alerts were activated in 12 regions of Ukraine, from Volyn in the north-west to Dnipropetrovsk in the south-east.
In a post on social media, Mr Klitschko urged Kyiv residents to "stay in shelters", warning of waves of drone attacks and a "difficult" night ahead.
He said at least two high-rising buildings in different districts of the capital were on fire after being hit by falling drone fragments.
Kyiv officials also reported that warehouses in the southern Holosiyivsky district were ablaze.
Some officials accused Russia of targeting Kyiv deliberately as residents prepared to celebrate Kyiv Day - the anniversary of the city's foundation 1500 years ago and a popular holiday before the war.
There were also reports of explosions in the city of Zhytomyr, west of Kyiv.
The air alert was later lifted in the capital and across the country.
In its recent attacks, Russia has been using so-called kamikaze drones as well as a range of cruise and ballistic missiles.
The attacks come ahead of a widely expected Ukrainian counter-offensive.
On Saturday, one of Ukraine's most senior security officials told the BBC the country was ready to launch such an operation.
Oleksiy Danilov, secretary of the powerful National Security and Defence Council of Ukraine, said an assault to retake territory from President Vladimir Putin's occupying forces could begin "tomorrow, the day after tomorrow or in a week".
Ukraine has been planning a counter-offensive for months. But it has wanted as much time as possible to train troops and to receive military equipment from Western allies.
In the meantime, Russian forces have been preparing their defences in the seized regions of south-eastern Ukraine.
Speaking to the BBC, Andrei Kelin, Russia's ambassador to the UK, said his country had "enormous resources" and it was yet to "act very seriously".
Warning that supplies of weapons to Ukraine risk escalating the war to levels not seen so far, he added: "Sooner or later, of course, this escalation may get a new dimension which we do not need and we do not want."
Bd-pratidin English/Lutful Hoque
