A massive fire has erupted on a bridge crossing to Crimea sending smoke and flames billowing into the sky, with a road section completely collapsed into the sea.
It comes days after a US official claimed that Ukraine could retake the region as Russia continues to flounder in its war.
Widespread images on social media show the bridge in the Kerch strait linking Russia with Crimea ferociously ablaze.
One video shows that a road section of the bridge has completely given way and collapsed into the sea while a freight train appears to be stationary and ablaze on the rail part of the key link between Russia and the Crimea that was opened in 2018.
Residents in the area have reported hearing powerful explosions at around 6am local time on Saturday morning.
A train on the bridge has caught fire, according to a Crimean official, reported the TASS agency.
Oleg Kryuchkov, adviser to the head of Crimea, said that a fuel tank has caught fire on one of the sections of the Crimean bridge and that the shipping arches are not damaged.
“Preliminarily, a fuel tank is on fire in one of the sections. The shipping arches are not damaged. It’s too early to talk about the causes and consequences. Work is underway to extinguish the fire,” Kryuchkov wrote in his Telegram channel.
Traffic over the Crimean bridge has been stopped by the Russian authorities, TASS added.
Vladimir Putin's forces have failed to make the swift progress through Ukraine that was expected by many at the start of the invasion and recently they have been forced to retreat in the south and east of the country.
In a video, Ukrainian President Volodymyr Zelensky has said his forces' latest offensive had liberated 940 square miles and 96 settlements in the country's east.
Reports of Russia's battlefield failures have provoked unusual public recrimination from Kremlin allies and regular reshuffles in the top brass.
With the Russian army being forced to retreat further on a daily basis recently, a US officer has reportedly said that "the recapture of Crimea by Ukraine is now a distinct possibility and can no longer be discounted."
Speaking to the Telegraph the official continued: "It is clear that Russia no longer has the ability or willpower to defend key positions, and if the Ukrainians succeed in their goal of recapturing Kherson, then there is a very real possibility that it will ultimately be able to recapture Crimea."
Russian news site RBC said Moscow had sacked the commander of its eastern military district, but gave no details of the reasons, while the army and the Kremlin offered no immediate comment.
Meanwhile, on Friday, Ukrainian authorities accused Russia of launching drone attacks on the southern city of Zaporizhzhia.
It is reported that external power to the Zaporizhzhia nuclear power plant has been cut off due to the shelling and emergency generators are being used.
Ukrainian troops fired six rockets that set fire to a railway fuel depot in the city of Ilovaisk in a Russian-occupied part of Donetsk, the Russian state news agency TASS said.
State television showed images of Putin meeting leaders of other former Soviet allies at an informal summit in St Petersburg, but commentators mentioned his 70th birthday on Friday only in passing.
Russian Orthodox Patriarch Kirill, a vocal supporter of the war, led Putin's birthday tributes with a prayer for god to grant him health, longevity, and deliverance from "visible and invisible enemies".
Ramzan Kadyrov, the leader of Chechnya, a once-breakaway region Putin reconquered two decades ago, congratulated "the number one patriot in the world".
Public celebrations were otherwise muted. In a video circulated on pro-Russian social media channels, a few hundred young people in St Petersburg waved Russian flags and held up red umbrellas to spell out "Putin - My President".
