Ukraine warned there would be emergency blackouts once again in several regions as it repaired damage from missile attacks it said destroyed homes and knocked out power, while Moscow accused Kyiv of attacking deep inside Russia with drones.
A new Russian missile barrage had been anticipated in Ukraine for days and it took place on Monday just as emergency blackouts were due to end, with previous damage repaired.
The strikes, which plunged parts of Ukraine back into freezing darkness with temperatures below zero Celsius (32 Fahrenheit), were the latest in weeks of attacks hitting critical infrastructure, reports Reuters.
At least four people were killed, Ukrainian President Volodymyr Zelenskiy said, adding that most of some 70 missiles were shot down.
"In many regions, there will have to be emergency blackouts," he said in a late Monday video address. "We will be doing everything to restore stability."
Moscow has been hitting Ukraine's energy infrastructure roughly weekly since early October in what it says is a bid to degrade Ukraine's military. Ukraine says such attacks are aimed at civilians and constitute war crimes. Moscow denies that.
People take shelter inside the metro station amid Russian missile attacks in Kyiv, Ukraine on December 5, 2022 — Reuters photo
The United States said it would convene a virtual meeting on Thursday with oil and gas executives to discuss how it can support Ukrainian energy infrastructure, according to a letter seen by Reuters.
US Secretary of State Antony Blinken said Russia would fail in its "current gambit of trying to, in effect, get the Ukrainian people to throw up their hands".
"The point is this, unless and until Russia demonstrates that it's interested in meaningful diplomacy, it can't go anywhere. If and when it does, we'll be the first to be ready to help out," he said at the Wall Street Journal CEO Council in Washington.
Russia says it is waging a "special military operation" in Ukraine to rid it of nationalists and protect Russian-speaking communities. Ukraine and its allies accuse Moscow of an unprovoked war to grab territory from its pro-Western neighbour.
Russia's defence ministry on Monday said Ukrainian drones attacked two air bases at Ryazan and Saratov in south-central Russia, killing three servicemen and wounding four, with two aircraft damaged by pieces of the drones when they were shot down.
Ukraine did not directly claim responsibility for the attacks. If it was behind them, they would be the deepest strikes inside Russia since Moscow invaded Ukraine on February 24.
The New York Times, citing a senior Ukrainian official, said drones targeting two military bases were launched from Ukrainian territory, and at least one of the strikes was made with the help of special forces close to the base.
Israeli satellite imaging company ImageSat International shared images it said showed burn marks and objects near a Tu-22M aircraft at the Dyagilevo airbase.
Russia's defence ministry said the attacks were acts of terrorism intended to disable long-range aircraft, and the low-flying drones were shot down. The deaths were reported on the Ryazan base, 185 km (115 miles) southeast of Moscow.
Russia responded with a "massive strike on the military control system" and other targets using high-precision air- and sea-based weapons in which all 17 objectives were hit, the defence ministry said.
Saratov is at least 600 km (370 miles) from the nearest Ukrainian territory. Russian commentators said on social media that if Ukraine could strike that far inside Russia, it might also be capable of hitting Moscow.
In Ukraine's southern Zaporizhzhia region, at least two people were killed and several houses destroyed by Russian missile strikes, the deputy head of the presidential office, Kyrylo Tymoshenko, said.
Reuters video showed two bodies covered with blankets lying next to a damaged car in the village of Novosofiivka, about 25 km (16 miles) east of Zaporizhzhia city.
"Both of my neighbours were killed," Olha Troshyna 62, said. "They were standing by the car. They were seeing off their son and daughter-in-law."
Missiles also hit energy plants in the regions of Kyiv and Vinnytsia in central Ukraine, Odesa in the south and Sumy in the north, officials said.
About half of the Kyiv region - which does not include the capital and which had a population of about 1.8 million before the war - will be without electricity in the coming days, the region's governor said.
Ukraine had only just returned to scheduled power outages from Monday rather than the emergency blackouts it has suffered since widespread Russian strikes on November 23, the worst of the attacks on energy infrastructure.
Ukraine's air force said it downed over 60 of more than 70 missiles fired by Russia on Monday.
At the frontlines in the east, Russian soldiers were attempting to cut roads to the town of Bakhmut in the Donetsk region from the west and northwest, Ukrainian presidential adviser Oleksiy Arestovych said on YouTube.
Donetsk Governor Pavlo Kyrylenko told Ukrainian television late on Monday that there were only about 12,000 people left in Bakhmut, from 80,000 before the war, and there was no electricity or gas.
“When power supply is being restored, the enemy deliberately hits power lines so that there is no power supply,” he said.