KYIV, Jan 14 (AFP) - Russia unleashed a new wave of major attacks on Ukraine on Saturday, hitting energy infrastructure across the country and killing at least 12 people in a missile strike on a nine-storey apartment building in the city of Dnipro, officials said.

Rescue teams toiled through the night in freezing temperatures in the aftermath of the Dnipro attack, in east-central Ukraine, with local officials saying people were still alive underneath the massive pile of wreckage.

"They keep sending SMS-es," Mikhailo Lysenko, deputy mayor of Dnipro said in a social media video. "We stop our work now and then to keep silence and we hear people scream from underneath the rubble."

Russian strikes also hit critical infrastructure in Kyiv and other places, with Ukraine's energy minister saying the coming days would be "difficult" with threats to the supply of electricity, running water and central heating at the height of winter.

President Volodymyr Zelenskiy said the number of those killed in the Dnipro apartment attack was likely to rise and he issued a fresh appeal to his Western allies for more weaponry to end "Russian terror" and attacks on civilian targets.

U.S. Ambassador to Ukraine Bridget Brink and Kyiv's other allies condemned Saturday's Russian attacks.

"More security assistance is coming to help Ukraine defend itself," Brink said on Twitter, calling the strike on Dnipro "horrifying."

Kyrylo Tymoshenko, deputy head of Zelenskiy's office, said 37 people had been rescued from the building and a total of 64 were injured. Zelenskiy said the second to ninth floors of the building's damaged section had collapsed.

Pictures posted on Dnipro Mayor Borys Filatov's Telegram account showed residents with no equipment desperately removing what remained of a wrecked car and combing through rubble against the background of a large pile of metal and concrete. Wounded people were carried away on stretchers.

"You used to come to our city! We treated you as normal people, as relatives. What have you done to my son?" a woman, restrained by rescuers, shrieked in a video from the scene.

Another person was killed and one wounded in the steel-making city of Kryviy Rih where six houses were damaged in Zelenskiy's hometown, mayor Oleksandr Vilkul said.