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Watch: People flee Kyiv building after explosion
Russia has hit Ukraine with a wave of attacks, dive-bombing the capital, Kyiv, with what appear to be Iranian-made "kamikaze" drones.
Critical infrastructure was hit in the Kyiv, Dnipro and Sumy regions, with electricity cut in hundreds of towns and villages, the government says.
At least eight people were killed, four in Kyiv and four in Sumy.
Calls have mounted for sanctions on Iran, which continues to deny supplying drones to the Russian military.
A week ago, the Ukrainian capital was hit by Russian missiles at rush hour, part of nationwide attacks which left 19 dead.
In the latest attack, starting at around 06:30 (03:30 GMT), 28 drones targeted the capital but only five hit targets, according to the Mayor, Vitaliy Klitschko.
The city 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.
National Police officers shooting down an Iranian drone.
WE NEED AIR DEFENSE! pic.twitter.com/AvdviH6RhE
In the Shevchenkivskyi district, rescuers searched for survivors in the ruins of a block of flats that partially collapsed after one attack. The street was cordoned off as dozens of firefighters and emergency staff worked at the scene. Among the four people killed in the district was a pregnant woman.
Across the street from the ruined building, the offices of Ukraine's energy company were also hit. The facility was probably the intended target of the strike.
Mayor Klitschko described the attacks as a "genocide of the Ukrainian people", saying, "The Russians need a Ukraine without Ukrainians."
The city authorities, he added, were expecting air defence systems to be delivered soon to protect the capital from further drone attacks.
"The enemy can attack our cities, but it won't be able to break us," said President Volodymyr Zelensky, describing the attacks as "terrorising the civilian population".
Despite an appeal from the mayor for people to seek shelter, the city's streets were far from deserted. Between two sets of strikes, plenty of people could be seen going about their business.
A Reuters news agency journalist reported seeing fragments of a drone used in the attack that bore the words "For Belgorod".
The Russian border city of Belgorod has been hit several times since Russia invaded Ukraine. Moscow blames Kyiv for the attacks.
In the other attacks:
The low buzzing of the slow-moving drones is becoming familiar across Ukraine.
Ukrainian presidential aide Mykhaylo Podolyak accused Iran of being "responsible for the murders of Ukrainians".
Some EU foreign ministers, including those from France and Germany, are calling for new sanctions against Iran for supplying drones to Russia.
EU foreign policy chief Josep Borrell said the bloc would investigate Tehran's participation in the conflict.
Despite the mounting evidence of Iranian drones being used, Iranian foreign ministry spokesperson Nasser Kanani insisted his country was not a "party in the war", adding: "We have not supplied any weapons to the sides of the Ukraine war."
Russia said it had hit Ukrainian military command facilities and energy systems "in the course of 24 hours" with long-range air- and sea-based weapons on Sunday.
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.
Russia has increased the use of combat drones in Ukraine as it seeks to avoid using long-range precision missions.
Additional reporting by Hugo Bachega in Kyiv, and Elsa Maishman and Patrick Jackson in London.
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