Tetyana Safonova looks at her mobile phone during a power outage on October 20, in Borodyanka, Ukraine.

Over 1.5 million energy subscribers in Ukraine have been left without power following another wave of Russian attacks, the deputy head of the Ukrainian President’s Office said Saturday.

Repairs started immediately to fix the outages, according to Kyrylo Tymoshenko, who shared the update on his Telegram channel.

Air sirens were activated across the country, except in Russian-annexed Crimea, according to the Ministry of Digital Transformation.

Remember: Ukraine has been facing a wide assault on critical infrastructure and power sources since Oct. 10. 

Government officials have warned of a potentially cold, dark winter.

Local leaders share the situation on the ground: The fresh series of attacks damaged infrastructure across central and western Ukraine, officials in various regions said Saturday.

Residents in the western city of Rivne were told to “stay in shelters” while electricians worked to restore power across the city, the head of the region’s military administration, Vitaliy Koval, said on Telegram. 

South of Rivne in Khmelnytskyi, the city council reported the entire city was without power after a series of explosions were heard. 

“Please stock up on water, if possible, because it will also disappear in an hour,” the council wrote on Telegram. 

Parts of Lutsk — in Ukraine’s far west — were left without power due to a hit on an energy facility there, Mayor Ihor Polishchuk said. He added rescuers were working to find anyone injured and that one civilian was burned in the blast, but no one appeared to have been killed.

An attack on an energy facility in the Kropyvnytskyi region of central Ukraine also left residents there and in neighboring Cherkasy without power, according to officials from both region’s military administrations. 

CNN’s Stephanie Halasz contributed to this report.