Russia on Saturday said three people were killed after a truck exploded on its bridge linking Crimea to mainland Russia - a symbol of its annexation of the peninsula - without immediately blaming Ukraine.
The blast ripped through the 19-kilometre bridge - hugely important to the Kremlin - more than seven months into Moscow's Ukraine offensive.
Dramatic social media footage showed the bridge on fire with parts plunging into the water.
"According to preliminary information, three people were killed," Russia's investigative committee said in a statement.
It said the bodies of a man and a woman had been pulled out of the water after the bridge had partially collapsed.
Moscow said they were likely to be passengers of a car that was driving near the exploded truck and that their identities were being established.
It also said that it had identified the owner of the truck as a resident of Russia's southern Krasnodar region, saying his place of residence was being searched.
Russia said the blast set ablaze seven oil tankers transported by train and collapsed two car lanes of the giant road and rail structure.
"Today at 6:07 am (0307 GMT) on the road traffic side of the Crimean bridge... a car bomb exploded, setting fire to seven oil tankers being carried by rail to Crimea," the national anti-terrorism committee said.
The bridge, personally inaugurated by President Vladimir Putin in 2018, is a vital transport link for carrying military equipment to Russian soldiers fighting in Ukraine.
It is hugely important to the Kremlin, and Moscow had maintained the bridge crossing was safe despite the fighting.
While some in Moscow hinted at Ukrainian "terrorism", state media continued to call it an "emergency situation."
Ukraine's presidential advisor Mykhailo Podolyak earlier took to Twitter posting a picture of a long section of the bridge half-submerged.
"Crimea, the bridge, the beginning," he wrote.
"Everything illegal must be destroyed, everything stolen must be returned to Ukraine, everything occupied by Russia must be expelled."
The Ukrainian post office announced it was preparing to print stamps showing the "Crimean bridge -- or more precisely, what remains of it".
The Kremlin spokesman said Putin had ordered a commission to be set up to look into the blast, Russian news agencies reported.
Officials in Moscow stopped short of blaming Kyiv.
But an official in Russian-installed Crimea pointed the finger at "Ukrainian vandals." Another in the neighbouring Kherson region said repairs could "take two months".
And the spokeswoman of Russia's foreign ministry said that Kyiv's reaction to the blasts showed its "terrorist nature."
'Undisguised terrorist war'
Some officials in Moscow and in Russian-occupied Ukraine called for retaliation.
"There is an undisguised terrorist war against us," Russian ruling party deputy Oleg Morozov told the RIA Novosti news agency.
A Russian-installed official in the occupied Ukrainian Kherson region, Kirill Stremousov, said: "Everyone is waiting for a retaliatory strike and it is likely to come."
There have been several explosions at Russian military installations in the Crimean peninsula.
If it is established that Ukraine was behind the latest blast, alarm bells may sound with the bridge so far from the front line.
The blasts come after Ukraine's recent lightning territorial gains in the east and south that have undermined the Kremlin's claim that it annexed Donetsk, neighbouring Lugansk and the southern regions of Zaporizhzhia and Kherson.
The Moscow-installed head of the peninsula, Sergei Aksyonov, called on Crimeans to remain "calm" as authorities appeared to downplay the blasts.
"I call on everyone to clam down and not spread fake information," he said on Telegram. "The situation is being controlled, professionals are working on the ground."
He said rail links to Russia had been halted and added that authorities had set up food and heating points to help stranded drivers.
Authorities also tried to calm fears of food and fuel shortages in Crimea, which is fully reliant on the Russian mainland since Moscow annexed it in 2014.
Border village shelled
On the same day, the governor of Russia's Belgorod region that borders Ukraine said Kyiv's forces had fired at a Russian border village, injuring a teenager.
On Friday, Russian forces said they had captured ground in Donetsk in east Ukraine, their first claim of new gains since a Kyiv counter-offensive rattled Moscow's war effort.
Separatist forces in the conflict-torn Donetsk region said they had retaken a series of villages near the Ukraine-controlled industrial town of Bakhmut, which has been under Russian shelling for weeks.
The Donetsk region, which has been partially controlled by Kremlin-backed separatists for years, is a key prize for Russian forces, which sent troops to Ukraine in February.
Ukrainian President Volodymyr Zelensky said late Friday his forces had recaptured nearly 2,500 square kilometres (965 square miles) in the counter-offensive that began late last month.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)
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