Russia has unleashed a wave of attacks on Ukraine targeting airfields, fuel facilities and gas fields in what appears to be the next phase of an invasion that has been slowed by fierce resistance.
Huge explosions lit up the sky early Sunday south of the capital, Kyiv, where people hunkered down in homes, underground garages and subway stations in anticipation of a full-scale assault by Russian forces.
Flames billowed into the sky before dawn from an oil depot near an air base in Vasylkiv, where there has been intense fighting, according to the town’s mayor.
President Volodymyr Zelenskyy’s office said another explosion was at the civilian Zhuliany airport.
Mr Zelensky’s office also said Russian forces blew up a gas pipeline in Kharkiv, the country’s second-largest city, prompting the government to warn people to protect themselves from the smoke by covering their windows with damp cloth or gauze.
The gas blast there sent a mushroom cloud up into the darkness.
"The enemy wants to destroy everything," said the mayor of Vasylkiv, Natalia Balasinovich.
Russia targeting 'critical civilian infrastructure'
The latest flurry of attacks signal a new tactic from Vladimir Putin, says Michael Kofman, a Russian military analyst in Washington DC.
"I think today we've seen a shift in Russian targeting towards critical civilian infrastructure, greater use of MLRS (Multiple Launch Rocket Systems), and artillery in suburban areas," he tweeted Sunday afternoon.
"Unfortunately, my concern that this was going to get a lot more ugly" with dire consequences for civilians "starting to materialise".
Amid reports Putin is frustrated with the staunch resistance he has encountered, there are growing concerns about how he will respond.
"My fear, looking at this 72 hours in, is all the worst is yet to come," Mr Kofman said.
Boy, 6, among reported Ukrainian civilian casualties
In early Sunday morning (local time) an air raid alert was issued in the capital Kyiv as people were advised to take cover.
According to reports, a six-year-old boy has died after being caught up in an attack on Kyiv.
The Ukraine National Specialised Children's Hospital was reported to have been damaged in an attack on Saturday. Three children were brought to the hospital, with one dying on arrival, CNN reported, citing the local hospital. However it is hard to verify such accounts.
Terrified men, women and children have sought safety inside and underground, as the Kyiv local government maintains a curfew to keep people off the streets.
More than 150,000 Ukrainians fled for Poland, Moldova and other neighbouring countries, and the United Nations warned the number could grow to 4 million if fighting escalates.
Earlier, Ukraine president said Ukrainian forces spent Saturday night "successfully repelling enemy attacks".
On Sunday, he called for an international legion of fighters, asking people from around the world to come and help defend Ukraine.
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