At least five explosions have been heard in the Ukrainian capital Kyiv - with a presidential adviser blaming "kamizake drones" sent by Russia.
"It shows their desperation," said Andriy Yermak, head of Ukrainian President Zelensky's office.
Mayor Vitalii Klitschko said residential buildings in the central Shevchenkivskiy area had been damaged.
A week ago, the capital was hit by Russian missiles at rush hour, part of nationwide attacks which left 19 dead.
The explosions on Monday began at around 06:30 local time (03:30 GMT), and there were at least five in total. The most recent was at around 08:10 local time.
Two were close to the city centre, with sirens and car alarms heard across the area.
Writing on the Telegram social media site, Mr Klitschko said there were explosions in the Shevchenkivskiy district, which was hit by several strikes last week.
He said rescuers were on site where a fire had broken out, and told residents to stay in air raid shelters.
Mr Yermak described the kamikaze attacks as Russia's "death throes", and that Ukraine needed more air defence systems "as soon as possible".
A local journalist, Oksana Kovalenko, told the BBC that two drones had hit critical energy-related infrastructure, and that one had been shot down.