The Ukrainian capital Kyiv has been hit by at least four explosions - with a presidential adviser blaming "kamizake drones" sent by Russia.
"It shows their desperation," said An officer fires at a flying drone stood in front of car.
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.
This morning's attacks were from drones - the low buzzing of these slow-moving weapons is becoming familiar across the country.
Kyiv reverberated to the rattle of gunfire as anti-aircraft batteries frantically tried to shoot them down. Video on social media appeared to show one interception.
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.
What's being targeted is hard to determine. The mayor's office says residential and non-residential buildings have been hit. Railway officials say explosions were seen close to Kyiv's main station.
Recent attacks have targeted Ukraine's energy infrastructure. It will be surprising if that's not the case today.
Writing on the Telegram social media site, Mr Klitschko said there were four strikes in Kyiv, although residents heard five or six explosions. He also told residents to stay in air raid shelters.
But despite the warnings, the streets are far from deserted. Between the first and second set of strikes, plenty of people seemed to be going about their Monday morning business.
Mr Yermak described the kamikaze attacks as Russia's "death throes", and that Ukraine needed more air defence systems "as soon as possible".
What are kamikaze drones?
- Small aerial weapons, also known as loitering munitions, which are destroyed after striking the target
- Unlike other drones - which are supposed to return home after dropping missiles - kamikaze drones are disposable
- The name derives from the Japanese pilots who volunteered to crash their planes in suicide missions in World War Two
- President Zelensky has previously accused Russia of using Iranian-made drones - Iran denies supplying them while Russia has not commented
Russian President Vladimir Putin said last week's strikes were in retaliation for the bombing of a key bridge linking Russia to occupied Crimea, which he blamed on Ukraine.
It was the first time during the war that the centre of Kyiv had been directly targeted.
Earlier this week, Mr Putin said there was no need for more large-scale strikes on Ukraine. Most designated targets had been hit, he said, adding that it was not his aim to destroy the country.