An overnight Russian missile strike killed at least 12 people in Zaporizhzhia, authorities said on Sunday, in the latest deadly attack to hit the southern Ukrainian city that President Volodymyr Zelensky called "absolute evil".

The reports came a day after a key bridge linking Russia with the annexed Crimea peninsula was partially destroyed by an explosion, and as the Kremlin replaced its top general amid major battlefield setbacks in Ukraine.

Zelensky said 12 people had died and 49 people, including six children, were in hospital after Russian missiles again hit Zaporizhzhia.

City council secretary Anatoliy Kurtev, provided a higher death toll of 17.

At least 17 people including a child also died when seven Russian missiles hit the centre of the industrial city earlier this week.

Regional official Oleksandr Starukh posted pictures of heavily damaged apartment blocks on Telegram and said a rescue operation had been launched to find victims under the rubble.

Zelensky denounced the "merciless strikes on peaceful people" and residential buildings as "absolute evil" perpetrated by "savages and terrorists".

Divers were to inspect the waters beneath the giant Crimea bridge Sunday a day after a truck bomb ignited a massive fire on the road and rail link, killing three people.

"We are ordering the examination by divers, they will start work from six in the morning," Russia's Deputy Prime Minister Marat Khusnullin announced.

"First results" of Russia's inspection of the bridge were due Sunday, he added.

Russia on Saturday said traffic had resumed over the strategic link symbolising the Kremlin's 2014 annexation of Crimea.

The 19-kilometre (12-mile) bridge was attacked at dawn, sparking celebrations from Ukrainians and others on social media, where dramatic footage showed it burning with a road section plunging into the water.

But Zelensky did not directly mention it in his nightly address and officials made no claim of responsibility.

Following the blast, the bodies of an unidentified man and a woman were pulled out of the water, likely passengers in a car driving near the exploded truck, Moscow said.

Authorities had identified the owner of the truck as a resident of Russia's southern Krasnodar region, saying his home was being searched.

- 'Emergency situation' -

The bridge is logistically crucial for Moscow, a vital transport link for carrying military equipment to Russian soldiers fighting in Ukraine.

It is also hugely symbolic. President Vladimir Putin personally inaugurated the structure in 2018 -- even driving a truck across -- and Moscow had maintained the link was safe despite the fighting.

While some in Moscow hinted at Ukrainian "terrorism", state media continued to call it an "emergency situation".

Zelensky's adviser Mykhailo Podolyak posted a picture on Twitter of a long section of the bridge half-submerged. "Crimea, the bridge, the beginning," he wrote.

But in a later statement, he appeared to suggest Moscow had a hand in the blast, noting the truck that detonated "entered the bridge from the Russian side".

The Kremlin's spokesman said Putin had ordered a commission to be set up to look into the blast.

Officials in Moscow stopped short of blaming Kyiv, but a Russian-installed official in Crimea pointed the finger at "Ukrainian vandals."

"There is an undisguised terrorist war against us," Russian ruling party deputy Oleg Morozov told the RIA Novosti news agency.

Military analysts said the blast could have a major impact if Moscow saw the need to shift already hard-pressed troops to the Crimea from other regions or if it prompted a rush by residents to leave.

Mick Ryan, a retired Australian major general now with the Center for Strategic and International Studies in Washington, said that even if Ukrainians were not behind the blast, it constituted "a massive influence operation win for Ukraine".

"It is a demonstration to Russians, and the rest of the world, that Russia's military cannot protect any of the provinces it recently annexed," he said on Twitter.

Authorities in Crimea tried to calm fears of food and fuel shortages in Crimea, dependent on the Russian mainland since annexation frm Ukraine.

- Moscow appoints new general -

The blast came after Ukraine's lightning territorial gains in the east and south that have undermined the Kremlin's official annexation of Donetsk, neighbouring Lugansk and the southern regions of Zaporizhzhia and Kherson.

After weeks of military setbacks that triggered unprecedented domestic criticism of Russia's army, Moscow on Saturday announced that a new general -- Sergei Surovikin -- would take over its forces in Ukraine.

Surovikin previously led Russia's military in southern Ukraine. He has combat experience in the 1990s conflicts in Tajikistan and Chechnya, as well as, more recently, in Syria.