By Henri Astier & Yaroslav Lukov
Russia has launched a "new massive strike" targeting Ukraine's energy grid, Ukrainian President Volodymyr Zelensky has said.
He said the attacks were on a "very wide" scale, hitting Ukraine's regions in the west, centre, south and east.
Nearly 1.5 million households were without electricity, Kyiv said.
But Mr Zelensky said most of the Russian missiles and drones were being shot down, and such strikes would not stop a Ukrainian military advance.
"Of course, we do not yet have the technical ability to shoot down 100% of Russian missiles and attack drones. We will gradually come to this - with the help of our partners, I'm confident of this," the Ukrainian leader said in his video address late on Saturday.
Almost a third of Ukraine's power stations and other energy-generating facilities have been destroyed in a wave of air strikes since Monday last week.
The areas targeted by the latest attacks include the Cherkasy region, south-east of the capital Kyiv, and the city of Khmelnytskyi, further west.
Air strikes and power disruptions were also reported from Odesa in the south to Rivne and Lutsk in the north-west.
The national electricity operator, Ukrenergo, said the strikes may have caused more damage than intense bombardment earlier this month.
President Zelensky said that 36 rockets had been launched on Saturday, and most of them had been downed.
Later, in his evening address, he said officials had managed to restore power in multiple regions of the country where electricity had been cut off as a result of the attack.
The deputy mayor of the western city of Lviv, Serhiy Kiral, told the BBC on Saturday that Russia's strategy was to damage critical infrastructure before the winter, and bring the war to areas beyond the front line.
"The more successes the Ukrainian armed forces are having at the front the worse it's going to be for people on the home front because Russia is going to do all it can to target civilians and to target critical infrastructure," he said in an interview with the Newshour radio programme.
On Friday Mr Zelensky accused Russia of planting mines at a hydroelectric dam in the Kherson region of southern Ukraine, which is under the control of Moscow's forces.
He said that if the Kakhovka hydropower plant was destroyed, hundreds of thousands of people would be in danger of flooding. Russia has denied planning to blow up the dam and said Ukraine was firing missiles at it.
The dam may provide Russia with one of the few remaining routes across the River Dnieper (called Dnipro by Ukrainians) in the partially occupied Kherson region.
Thousands of civilians have been leaving the city of Kherson in recent days, as Ukrainian forces advance.
And on Saturday a new directive from occupying Russian authorities was released, renewing its appeal for civilians to leave "immediately".
The transfer or deportation of civilians by an occupying power from occupied territory is considered a war crime. In September, the UN said there were already credible accusations of forced deportation of Ukrainian children from Russian-occupied areas.
Russia's ambassador to the UN, Vasily Nebenzia, said the allegations were unfounded.
Meanwhile, Ukraine's armed forces said that Russian troops on Saturday had left two villages - Charivne and Chkalove - in Kherson region. The claim has not been independently verified.
Across the border, in Russia's Belgorod region, the local governor said two people had been killed in Ukrainian shelling.