Russia’s Federal Security Service (FSB) claimed on Wednesday that Ukraine’s chief of intelligence was behind the attack on the Crimean bridge over the weekend which Moscow has dubbed a "terrorist attack."

Five Russians and three citizens of Ukraine and Armenia were detained Wednesday in connection with the bombing, the successor agency to the infamous KGB said, according to Russian stated owned media TASS. 

Ukraine has not said whether it was involved in the attack that damaged the 12-mile long bridged prized by Russian President Vladimir Putin and opened in 2018.

Crimea bridge

A screen grab from a surveillance footage shows flames and smoke rising up after an explosion at the Kerch bridge, also known as the Crimean Bridge, in the Kerch Strait, Crimea, Oct. 8, 2022.  (Security Camera/Anadolu Agency via Getty Images)

PUTIN ACCUSES UKRAINE OF 'TERRORISM' IN CRIMEA BRIDGE EXPLOSION

However, the FSB claimed the crushing blow was organized by the head of Ukrainian military intelligence, Kyrylo Budanov, who could now be under the immense threat of Russian reprisal, argued one Russia expert. 

"The Russian federal law, ‘On Countering Extreme Activity,’ which Putin approved in 2002, two and a half years after he assumed the presidency, and updated in 2006, authorizes targeted assassinations for ‘extremist activity’ and terrorism," former intelligence officer for the Defense Intelligence Agency, Rebekah Koffler, explained to Fox News Digital.

"There’s no available information that Budanov’s life is in immediate danger," she said, pointing out that Ukrainian security services has successfully protected top official like President Volodymyr Zelenskyy.

Chief of the Main Intelligence Directorate of the Ministry of Defense of Ukraine Kyrylo Budanov, Head of the Office of the President of Ukraine Andrii Yermak (L to R) are pictured during the briefing on the Return of the Defenders of Ukraine from Russian Captivity, Kyiv, capital of Ukraine, Sept, 22, 2022. 

"But based on the Russian Doctrine of the so called ‘wet affairs’ – spilling of the blood – the risk to Budanov’s life has just increased," Koffler added. 

EXPLOSION ROCKS KERCH BRIDGE CONNECTING RUSSIA AND CRIMEA, 3 DEAD: OFFICIALS

The FSB said the explosive used Saturday was camouflaged in rolls of construction polyethylene film on 22 pallets, weighing 22.7 tonnes, and was transported from Ukraine to Russia via Bulgaria, Georgia and Armenia.

Explosion causes fire at the Kerch bridge, also known as the Crimean Bridge, in the Kerch Strait, Crimea, Oct. 8, 2022. 

"Control over the movement of cargo along the entire route and contacts with participants in the criminal transportation scheme was carried out by an employee of the Main Intelligence Directorate of the Ministry of Defense," the FSB reportedly said in a statement.

The bridge connecting occupied Crimea to mainland Russia has been vital in supplying Putin’s troops in Ukraine by funneling logistical needs into southern Ukraine. 

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Crimea bridge

Workers restore the railway tracks on the Kerch bridge that links Crimea to Russia, near Kerch, on Oct. 9, 2022, a day after it was damaged by a blast. (AFP via Getty Images)

The explosion damaged one section of the road bridge and temporarily stopped traffic which has reportedly been partially restored, according to Moscow. 

Several fuel tankers on a train heading towards Crimea were also destroyed in the blast that killed three.

Russia responded to the explosion by firing a barrage of missile and drone strikes across Ukraine Monday.