Russian divers were examining 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 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.
Shelling kills 12, hurts dozens
At least 12 people were killed and 49 hospitalised, including six children, as a result of shelling in Ukraine's southeastern city of Zaporizhzhia, the region's governor said on Sunday.
A nine-storey building was partially destroyed overnight, five other residential buildings levelled and many more damaged in 12 Russian missile attacks, said Oleksandr Starukh, the governor of the Zaporizhzhia region.
"There may be more people under the rubble," Starukh said on the Telegram messaging app. "A rescue operation is underway at the scene. Eight people have already been rescued."
City official Anatoliy Kurtev had said earlier at least 17 people were killed when missiles hit a high-rise apartment complex and buildings.
Reuters could not independently verify the reports.
The city is about 125 km from a Russian-held nuclear power plant that is Europe's largest. Kyiv and Moscow have blamed each other for shelling at the Ukrainian-operated facility, which has damaged buildings and threatens a catastrophic nuclear accident.
- Reuters