An air raid alert has been issued across Ukraine, as a fresh wave of Russian missiles targets major cities.Presidential adviser Mykhailo Podolyak said more than 120 missiles had been launched at the population and civilian infrastructure.
At least two explosions were heard in the capital Kyiv, but it was unclear whether these were caused by missile strikes or air defences.
Blasts were also heard in the cities of Kharkiv, Odesa, Lviv and Zhytomyr.
The regional leader of the southern province of Odesa, Maksym Marchenko, spoke of a "massive missile attack on Ukraine".
The Ukrainian Air Force said Russia was attacking the country from "various directions with air and sea-based cruise missiles". It added that a number of Kamikaze drones had also been used.
Air raid alerts sounded in all regions of the country on Thursday morning. Presidential adviser Oleksiy Arestovych urged civilians to seek shelter and said the country's air defences were operating.
In Kyiv, the city military administration said debris from a downed rocket had struck a private building, and Mayor Vitaliy Klitschko said "several explosions" had been reported in the capital.
In the southern region of Mykolaiv, Governor Vitaly Kim wrote that five missiles were intercepted by air defences.
And in the Western city of Lviv Mayor Andriy Sadovy said several explosions had been reported.
Mr Podolyak accused Moscow of seeking "to destroy critical infrastructure and kill civilians en masse".
Dozens of Russian attacks have pounded Ukraine in recent weeks, causing repeated power cuts across the country. The latest attacks have already sparked power cuts in Odesa and Dnipropetrovsk.
"They are introduced due to the threat of missile attacks, in order to avoid significant damage if the enemy manages to hit energy facilities," the DTEK energy supplier wrote.
Oleksandr Vilkul, head of the Military Administration in the central city of Kryvyi Rih, said missiles fired at his city had been launched from Russian "ships and planes from the Black Sea". Power in the city had been switched off as a "precaution", he added.
Ukraine's southern command had already issued a warning that Russian force were preparing to launch up to 20 missiles from positions in the Black Sea.
In one barrage earlier this month, Ukraine shot down 60 of more than 70 missiles fired by Russian forces. Moscow has repeatedly denied targeting civilians in its missile strikes.
However, President Vladimir Putin has recently admitted that Russian troops have been hitting Ukraine's critical energy facilities.
The admission followed allegations from some international leaders, including French President Emmanuel Macron, that targeting energy facilities could amount to a war crime.
The government in Kyiv has pleaded with Western leaders to provide it with additional air defences, and US President Joe Biden recently agreed to supply its Patriot system.
