The attack on the Kerch Bridge to Crimea stunned both Ukrainians and Russians with its scale and ingenuity, leaving experts wondering who was responsible for the attack and how it was pulled off.
From a truck bomb to a submarine attack, military experts and analysts have put forth various theories about the cause of Saturday’s explosion on the 12-mile road and rail link to the peninsula annexed by Russian President Vladimir Putin in 2014, though their findings are inconclusive.
“It is too early to be definitive about the cause of the explosion based on publicly available information,” said NR Jenzen-Jones, arms and ammunition specialist at Armament Research Services.
The bridge has been a Ukrainian obsession ever since it was one of Putin’s flagship infrastructure projects. Viktor Andrusiv, who was an adviser at the Kyiv Interior Ministry until July, said he had been part of a working group with the army to investigate viable options to destroy it.
“It is not an easy task, not at all,” said Andrusiv, who has publicly called for the bridge to be destroyed for months. “It is a very well protected object, from the air, from the sea, from the ground.”
Was a missile used?
Most defense experts believe that this type of attack is unlikely. The bridge was out of range of the US-supplied Kyiv Himars, a medium-range guided artillery rocket system, and US defense officials warned they would not be used on the bridge, according to a US and Ukrainian official.
But two homegrown Neptune anti-ship missiles they were used to destroy the Moskva, the flagship of the Russian Black Sea Fleet, in April, indicating Ukraine’s ability to effectively use this type of airstrike against Russia, albeit at shorter ranges.
Those surprisingly precise hits suggest Western allies may be providing technical help to fine-tune Ukrainian weapons, analysts say. They have so far rejected Ukrainian requests for longer-range US-made missiles that can be fired from Himars.
“Check for cloudy weather, thunder, rain?” a Western official said, when asked what caused a section of the bridge to collapse. This was perhaps a cryptic reference to the Grim2, a Ukrainian missile with a theoretical range of up to 500km that has been in development for decades. Grim, and the missile’s previous name, Grom, are Ukrainian words for thunder. Ukrainian President Volodymyr Zelenskyy also described the weather in Crimea as “cloudy” on his late-night broadcast on Saturday.
Did a truck bomb cause the damage?
The most popular theory was a bomb blast from a white truck identified in images online. “There was something in the truck that exploded,” said a structural engineer, now in a specialized branch of the Ukrainian military, who analyzed the videos. “Something special.”
A ball of fire appeared on cameras just as the truck was parallel to a train carrying fuel, adding to the conflagration that reduced traffic on the bridge to a single lane for vehicles and trains. If it was a truck bomb, he said it could indicate it was followed from the air or by another vehicle whose pilot or driver could relay the optimal moment to detonate. Russian investigators say three people were killed in the blast, but it is not known whether they were participants or innocent bystanders.
Serhiy Kuzan, an adviser to the Ukrainian Defense Ministry, disagreed, pointing to two contiguous attacks in his analysis of publicly available footage. “We see that the supporting construction of the highway bridge is destroyed in two places,” he said, adding that blaming a truck allows Russia to define it as terrorism rather than a targeted military attack.
But Andrusiv came to the same conclusion as the structural engineer turned soldier. “It was a truck bomb and, most likely, the truck was also transporting agricultural chemicals,” he said, suggesting that the size of the explosion was amplified by the contents of the truck.
Is a submarine attack plausible?
The granularity of the available footage has given rise to several less plausible theories. Some videos appeared to show a boat traveling under the bridge at the time of the explosion. “Possibly an explosive aboard a remote controlled ship with a sensor for detonation when it passed under a structure?” tweeted OSINT Amateur, a little open source research cluster.
However, a photograph of the underside of the collapsed bridge, also shared on social media, showed no burn marks or wrinkled metal to indicate an explosion traveling from the water’s surface.
Photos of an unmanned maritime drone reaching the shores of Crimea were shared on social networks earlier this year, indicating that Ukraine could carry out a submersible attack.
Who carried out the strike?
Military experts believe that Ukraine’s intelligence services are the most likely branch of the Kyiv security apparatus that carried out the assault.
Andrusiv said the joint working group had considered missiles, unmanned aerial vehicles, underwater drones, stealth boats and a truck bomb. The Ukrainian missiles did not have accuracy at that range, and the other options needed specialized weapons which they did not have. They did not reach a conclusive evaluation.
A Western adviser described intelligence services combining NATO-like capabilities with Mossad-style mystique for their covert operations during the seven-month conflict with Russia. These have included special operations deep within occupied regions using partisan and elite forces.
But Ukraine and its allies’ strategy of disinformation, evasion and counter-accusation over the audacious attack allows them to sow disinformation or at least confusion, and keeps the Kremlin, as well as influential military bloggers and aggressive TV presenters, guessing at Ukraine’s capabilities.
Mykhailo Podolyak, Zelenskyy’s adviser, even suggested that infighting between different power centers in Moscow was behind the attack. “This is a concrete material manifestation of the conflict between the [intelligence services] on one side and the [military] on the other,” he told the FT.
As evidence, he pointed to the fact that the truck seen in the videos was driving from Russia to Crimea. “The logistics of the detonation. . . all of this clearly points to the Russian trail,” she said. Russia’s president said Sunday night there was “no doubt” Ukraine was behind the blast, calling it a terror attack.
Jenzen-Jones said the signal sent by the attack was stronger than its physical impact, as only one of the two lanes appears to be destroyed.
“If the damage to the Kerch bridge was indeed the result of a Ukrainian attack, it represents a propaganda rather than an operational victory.”