KYIV, Ukraine — A fireball consumed two sections of the only bridge linking the occupied Crimean Peninsula to Russia on Saturday, disrupting the most important supply line for Russian troops fighting in southern Ukraine and dealing an embarrassing blow to the Kremlin, which is facing continued losses on the battlefield and mounting criticism at home.
The blast and fire sent part of the 12-mile Kerch Strait Bridge tumbling into the sea and killed at least three people, according to the Russian authorities. A senior Ukrainian official corroborated Russian reports that Ukraine was behind the attack. The official, speaking on the condition of anonymity because of a government ban on discussing the blast, added that Ukrainian’s intelligence services had orchestrated the explosion, using a bomb loaded onto a truck being driven across the bridge.
For President Vladimir V. Putin of Russia, who presided over the bridge’s opening in 2018, the explosion was a highly personal affront, underscoring his failure to get a handle on a relentless series of Ukrainian attacks.
The explosion is emblematic of a Russian military in disarray. Russian forces were unable to protect the bridge, despite its centrality to the war effort, its personal importance to Mr. Putin and its potent symbolism as the literal connection between Russia and Crimea.
Hours after the explosion, the Kremlin appointed Gen. Sergei Surovikin, yet another new commander, to oversee its forces in Ukraine. Previous leadership shake-ups have done little to right the military’s floundering performance.
The full extent of the damage was not immediately clear. The bridge has sections for train and automobile traffic. By Saturday evening, the railroad section of the bridge had undergone repairs and a train with 15 cars had successfully crossed the span, according to a Russian state news agency, Tass. Car traffic had also resumed on the undamaged side of the bridge, the head of Crimea, Sergei Aksyonov, said in a post on Telegram.
Even so, Russian officials and hard-line military bloggers were already calling for revenge, with one member of Crimea’s Parliament warning that anything less than an “extremely harsh” response would show weakness.
Any serious impediment to traffic on the bridge could have a profound effect on Russia’s ability to wage war in southern Ukraine, where Ukrainian forces have been fighting an increasingly effective counteroffensive. The bridge is the primary military supply route linking Russia with the Crimean Peninsula. Without it, analysts said, the Russian military will be severely limited in its ability to bring fuel, equipment and ammunition to Russian units fighting in the Kherson and Zaporizhzhia regions, two of the four Ukrainian provinces that Mr. Putin announced Russia had annexed on Sept. 30.
Russia’s National Anti-Terrorism Committee said in a statement that a truck had exploded on the automobile side of the bridge, igniting seven fuel cisterns being pulled by a train on a parallel rail line headed in the direction of Crimea.
It was unclear if the driver of the truck, who died in the blast, was aware there were explosives inside. In video captured by a surveillance camera on the bridge, a huge fireball is seen, seeming to consume several vehicles. A small sedan and a tractor-trailer truck driving side by side appear at the epicenter of the blast. The explosion caused two sections of the bridge to partly collapse.
For the Ukrainians, the explosion “is not necessarily a decisive victory, but the balance of war often turns on an accumulation of lesser victories,” said Ben Barry, a senior fellow at the International Institute for Strategic Studies, a research group based in London. “It is another ratchet of the pressure on President Putin.”
While there were no official claims of responsibility, Ukrainian officials, who in the past have said the bridge would be a legitimate target for a strike, indicated that the explosion was no accident and made no secret of their satisfaction.
“Crimea, the bridge, the beginning,” Mykhailo Podolyak, an adviser to Ukraine’s president, wrote in a Twitter post on Saturday. “Everything illegal, must be destroyed. Everything stolen returned to Ukraine. All Russian occupiers expelled.”
Ukraine’s domestic intelligence agency, the Security Service of Ukraine, known by its Ukrainian acronym S.B.U., issued a statement rephrasing a stanza of a poem by Ukraine’s national poet, Taras Shevchenko. “Dawn, the bridge is burning beautifully,” the agency posted on Twitter. “A nightingale in Crimea meets the S.B.U.”
President Volodymyr Zelensky of Ukraine seemed to allude to the attack when he noted in his nightly address that Saturday “was a good and mostly sunny day” in Ukrainian territory. “Unfortunately, it was cloudy in Crimea,” he said.
The Kremlin’s spokesman, Dmitri S. Peskov, referred to the episode as an “emergency” in a statement on Saturday. He said that Mr. Putin, who had celebrated his 70th birthday on Friday, had been briefed.
“The president directed the prime minister to form a government commission to find out the causes of the incident and eliminate the consequences as soon as possible,” Mr. Peskov said, according to Russian state media.
Occupation officials in Crimea left little doubt about who they thought was responsible.
“Ukrainian vandals were able to reach the Crimean bridge with their bloody hands,” said Vladimir Konstantinov, the head of Crimea’s Kremlin-installed Parliament.
In recent weeks, military traffic heading across the bridge into Crimea has increased, as Russia has raced tanks and artillery equipment to the front lines in the Kherson region, a fertile slice of southern Ukraine that the Kremlin’s forces occupied in the first weeks of the war.
Ukrainian forces have stepped up their counteroffensive in the region, recapturing significant amounts of land in an effort to drive Russian forces east across the Dnipro River and liberate the city of Kherson, the only regional Ukrainian capital that Russian forces control.
Without the Kerch Strait Bridge, particularly the railroad section, the Kremlin would have few good options for supplying these troops with fuel and military equipment from their stocks in Russia, analysts said. Ferrying supplies by ship or plane to Crimea would be much more cumbersome, experts said. And a possible alternative overland supply route using southern Ukrainian territory seized by Russian forces would be vulnerable to Ukrainian attack and require the use of trucks, as there are no functioning rail lines.
“Essentially all heavy military traffic passed through the bridge, tanks, artillery and so on,” said Konrad Muzyka, a military analyst with Roshan Consulting.
In a statement, Russia’s defense ministry said troops in southern Ukraine would be supplied “fully and without interruption” by ground and sea, though it did not explain how this might be accomplished.
Ukraine’s monthlong blitz to retake territory from retreating Russian forces in the northeast of the country continued on Saturday, and Russia stepped up its bombardments of civilian infrastructure from the air.
Early on Saturday the recently liberated city of Kharkiv was rocked by explosions. Photos of an explosion showed a red fireball lighting up the night sky, enveloped by a billowing cloud of dark smoke. Buildings, including a medical institution, were on fire, Kharkiv’s mayor, Igor Terekhov, wrote on Telegram. It was not immediately known whether there were deaths or injuries.
Almost at the same time, Russian shelling also damaged the last line connecting the Zaporizhzhia nuclear power plant to Ukrainian energy systems, cutting it off from the power grid that is used to cool its reactors. The plant, Europe’s largest, has been disconnected from external power at least twice before, forcing it to rely on diesel generators to power safety equipment.
Herman Galushchenko, Ukraine’s energy minister, said in a Facebook post on Saturday that there was only enough diesel fuel to operate the plant for about 10 days, adding that the professionalism of Ukrainian nuclear workers was now the only “safeguard against a possible nuclear accident.”
Whether or not Ukraine takes responsibility for the bridge blast, the episode is redolent of other attacks carried out by Ukrainian forces against targets that were highly symbolic and showcased Ukraine’s military ingenuity in the face of a much stronger, more heavily armed Russian military.
In April, two Ukrainian-made Neptune cruise missiles, a weapon system that had never before been used in battle, slammed into the hull of the Moskva, the flagship of Russia’s Black Sea fleet. The strike set off a series of explosions that eventually caused the cruiser to sink, killing an unknown number of sailors, including possibly the ship’s captain.
While the attack on the Moskva stunned Russia’s military establishment, it was a series of explosions over the summer at military targets in Crimea that truly underscored Ukraine’s ability to strike at Russia’s pride as well as its army. The attacks, including on the critical Saki Air Base, shattered the illusion that Crimea, the crown jewel of Mr. Putin’s years of conquest in Ukraine, would be spared violence during the war.
Seized by Mr. Putin’s forces in 2014 and illegally incorporated into Russia shortly after, Crimea has steadily transformed from a quiet summer resort destination in southern Ukraine into a beachhead of military operations which, before the war, had become a symbol of Russia’s imperial resurgence.
The bridge itself is an engineering marvel that cost an estimated $7.5 billion and for the first time created a physical link between the Russian Federation and Crimea, which for centuries was part of the Russian Empire before being given by the Soviet government to Ukraine in the 1950s, in what was then a largely ceremonial gesture.
The bridge allowed easier access to Crimea not only for Russian tourists, but also for Russia’s military, which transported weapons and equipment into the peninsula in the years before February’s invasion.
It was from Crimea that Russian forces attacked southern Ukraine, quickly gobbling up large swaths of the Kherson and Zaporizhzhia regions in the Kremlin’s most successful operation in the war to date.
But, as the attack on the bridge underscored, that success seems increasingly imperiled.
After the explosion, Russian officials, along with the country’s increasingly bellicose military bloggers, did not wait for confirmation that Ukraine was responsible, calling for a swift and devastating response.
“If this time, we do not respond or do not respond just so, it will show definitively that we are weak,” said Sergei Mironov, the leader of a pro-Kremlin political party. “This extreme audacity requires an extremely harsh response.”
Reporting was contributed by Maria Varenikova in Kryvyi Rih, Ukraine, Megan Specia in Kyiv, Ukraine, Cassandra Vinograd in London and Katrin Bennhold in Berlin.
