By Catherine Byaruhanga in Kyiv & James FitzGerald
More strikes have been reported across Ukraine, days after one of Russia’s most intense bombardments of the war.
Officials say a gas production facility and a missile factory in Dnipro were among the latest targets and that at least four people died in one area.
In recent weeks, Russia has looked to target key Ukrainian energy infrastructure, following a series of battlefield setbacks.
Moscow has not yet commented on Thursday’s alleged attacks.
Four people died as a result of an overnight strike on residential buildings in the Zaporizhzhia region, according to the president’s office.
Meanwhile, missiles hit one of Ukraine’s largest cities, Dnipro, said the regional head – causing a fire at an industrial facility and 14 injuries.
The prime minister added that the city’s Pivdenmash factory – which produces missiles, among other products – had been bombed.
Nearby, 70 shells were said to have landed around the city of Nikopol, damaging infrastructure and leaving thousands of homes without power and water.
More infrastructure was targeted in the Odesa and Kharkiv regions, causing three injuries in each place, according to updates from officials.
The capital, Kyiv, was just one place where air raid sirens sounded. At about 08:00 local time (06:00 GMT), mobile phones started pinging with official warnings of a new nationwide missile attack.
Local air defences swung into action and military authorities reported that two cruise missiles and at least two Iranian-made drones had been shot down.
The head of the Lviv region said he did not yet have confirmation that air defences had been operating there as well.
Responding to Thursday’s strikes across the country, the head of the president’s office accused Russia of attempting a “strike in the back”.
Andriy Yermak added that this was a “naïve tactic” that his compatriots were able to withstand.
Ukrainians have been observed to be taking air raid alerts more seriously after another wide-ranging assault on Tuesday.
Dozens of long-range missiles pounded Ukraine that day, in what was believed to be the most intense barrage since the start of the war.
Late on Tuesday evening, fears were raised of a dangerous escalation in the war when one rocket landed outside Ukraine, killing two people in a village in Poland near the shared border.
Although President Volodymyr Zelensky was at first insistent that this had been fired by Russia, Kyiv’s allies said it instead appeared to have been sent by Ukrainian air defences.
Many missiles that were fired by Russia on Tuesday were intercepted – but those that did manage to strike infrastructure targets had the effect of further depleting Ukraine’s power reserves.
This has been a recent Russian tactic following a series of battlefield setbacks and its impact is starting to be felt more acutely.
Residents of Kyiv woke up to a blanket of snow on Thursday morning. Emergency power shutdowns have meant that many people are not able to heat their homes.
America’s top general has warned that Kyiv’s chances in the short term of winning the war by taking back all Russian-occupied land are “not high, militarily”.
Gen Mark Milley acknowledged, however, that there could be a “political solution” in which Russia made a decision to withdraw – saying the invading power was “on its back”.
In recent days, there has been optimism on the Ukrainian side following the recapture of the southern city of Kherson.
Reports have now emerged of civilians being tortured during the Russian occupation there. Russia has repeatedly denied committing atrocities during the conflict.
In other developments, the Ukrainian government has said a deal that allows it to export of grain by ships on the Black Sea has been extended for another 120 days.
The agreement, which was brokered by the UN and Turkey, has allowed millions of tonnes of produce to be shipped out of Ukraine in recent months – easing worries about global food security.
Before it was implemented in July, Russia had been blocking Ukraine’s Black Sea ports.