Russian divers were to examine on Sunday the damage left by a powerful blast on a road-and-rail bridge to Crimea that is a prestigious symbol of Moscow's annexation of the peninsula and a key supply route to forces battling in southern Ukraine.
Saturday's explosion on the bridge over the Kerch Strait prompted gleeful messages from Ukrainian officials but no claim of responsibility. Russia did not immediately assign blame.
Russian deputy prime minister Marat Khusnullin said the divers would start work in the morning, with a more detailed survey above the waterline expected to be complete by day's end, domestic news agencies reported.
"The situation is manageable - it's unpleasant, but not fatal," Crimea's Russian governor, Sergei Aksyonov, told reporters. "Of course, emotions have been triggered and there is a healthy desire to seek revenge."
The peninsula had a month's worth of fuel and more than two months' worth of food, he said. Russia's defence ministry said its forces in southern Ukraine could be "fully supplied" through existing land and sea routes.
Russia seized Crimea from Ukraine in 2014 and the 19-km Crimea Bridge linking the region to its transport network was opened with great fanfare four years later by Russian president Vladimir Putin.
Kyiv demands that Russian forces leave the Black Sea peninsula, as well as Ukrainian territory they seized in the invasion Putin launched in February.
The bridge is a major artery for the Russian forces that control most of southern Ukraine's Kherson region and for the Russian naval port of Sevastopol, whose governor told locals, "Keep calm. Don't panic."
It was not yet clear if the blast was a deliberate attack, but the damage to such a high-profile structure came amid battlefield defeats for Russia, and could further cloud Kremlin reassurances that the conflict is going to plan.
On Saturday, Putin signed a decree for tighter security for the bridge, as well as the infrastructure supplying electricity and natural gas to Crimea, and ordered an investigation.
"Conceivably the Russians can rebuild it, but they can't defend it while losing a war," said political analyst James Nixey of Britain's Chatham House think tank.
Russian officials said three people had been killed, probably the occupants of a car travelling near a truck that blew up. On the bridge's upper level, seven fuel tanker wagons of a 59-wagon train heading for the peninsula also caught fire.
Limited road traffic resumed about 10 hours after the explosion, and Russia's transport ministry cleared rail traffic to restart.
In the southeastern Ukrainian city of Zaporizhzhia, 125 km from a Russian-held nuclear power plant that is Europe's largest, Russian missile attacks killed at least 12, and sent 49 to hospital, the regional governor said on Sunday.
A nine-storey building was partially destroyed, five residential buildings levelled and many more damaged in a dozen attacks, Oleksandr Starukh, the governor, said on the Telegram messaging app.
"There may be more people under the rubble," he warned, with eight rescued.
Earlier, city official Anatoliy Kurtev had estimated at least 17 deaths, while the military's central command said the number of victims could run into dozens.
Reuters could not independently verify the reports.
'Happy Birthday, Mr President'
The Kerch bridge blast came a day after Putin's 70th birthday, coinciding with Russia's third senior military appointment in a week. It designated Air Force General Sergei Surovikin to take charge of the invasion effort.
Ukrainian president Volodymyr Zelenskiy did not refer to the blast in a video address on Saturday, saying merely that the weather in Crimea was cloudy.
"But however cloudy it is, Ukrainians know ... our future is sunny," he added. "This is a future without occupiers, across our territory, particularly in Crimea."
The head of Ukraine's National Security and Defence Council posted a video of the bridge on social media alongside a video of Marilyn Monroe singing "Happy birthday, Mr President".
Since the war started on February 24th, Ukrainian officials have regularly suggested they wanted to destroy the bridge. Ukraine's postal service said it would print a special stamp.
"Undoubtedly, we are witnessing the beginning of large-scale negative processes in Russia," Zelenskiy adviser Mykhailo Podolyak said in a commentary, blaming infighting among Putin's circle as he attributed the blast to Russian operators.
Russian foreign ministry spokeswoman Maria Zakharova said Kyiv's reaction to the destruction of civilian infrastructure "testifies to its terrorist nature".
The Russian National Anti-Terrorism Committee said a freight truck had blown up on the bridge's roadway at 6:07 a.m. (0307 GMT). It said two spans of road bridge had partially collapsed, but that the arch spanning the channel through which ships travel between the Black Sea and Azov Sea was not damaged.
Emergencies Minister Alexander Kurenkov told state news agency TASS that quick-thinking railway workers who uncoupled the burning fuel wagons had kept the blaze from spreading.
Images showed half of the roadway blown away, with the other half still attached.
While the blast would "not affect army supply very much", there would be problems with logistics for Crimea, Kirill Stremousov, the Russian-installed deputy administrator of the Kherson region, said in a social media post. -Reuters