Ukrainian President Volodymyr Zelenskyy said his country must "ensure that no Russian strike goes unpunished," after Russia unleashed a major missile and drone attack on Kyiv early Friday, killing at least six people.

"Today alone, in Kyiv only, six people were killed in a Russian attack. My condolences to their families and loved ones. More than 30 people were injured, including children. There were also strikes on our other cities and villages," Zelenskyy said in his daily briefing.

Russia's major attack on the Ukrainian capital left gaping holes in apartment buildings and started fires as the sound of explosions boomed across the city.

A pregnant woman was among at least 35 people wounded, Ukrainian authorities said.

The attack was the biggest on Kyiv in almost three weeks.

Most recent Russian aerial attacks have targeted electricity infrastructure around the country ahead of the bitter winter months.

Moscow denies targeting civilian areas, with the Russian Defense Ministry saying Friday it carried out an overnight strike on Ukraine’s “military-industrial and energy facilities.”

Ukrainian officials scoff at those claims, showing repeated damage to homes and public buildings.