Russia's Federal Security Service (FSB) Wednesday detained "five Russian nationals and three Ukrainians and Armenians" over the Crimea Bridge explosion on Saturday.

FSB officials blamed Ukrainian military intelligence and its chief, Kyrylo Budanov, for the Crimea Bridge Blast. It claimed the explosive device traveled from Odesa in Ukraine to Russia through Bulgaria, Georgia, and Armenia, per a report from Reuters.

According to Russian news agency TASS, 12 individuals were identified as accomplices.

Al Jazeera reported that the 25-year-old Crimean man who owned the truck from which the explosion is believed to have originated was responsible for the incident.

The man claims he is innocent because his uncle was driving the vehicle killed in the Crimea Bridge Blast.

The FSB, the primary successor to the KGB of the Soviet period, said that it had foiled Ukrainian strikes on both Moscow and the western Russian city of Bryansk.

Though the Ukrainian government has not admitted responsibility for the bridge bombing, some Ukrainian authorities have cheered the destruction.

A part of the twelve-mile-long bridge was destroyed by the explosion, which stopped traffic for a while. It also blew up many gasoline tanks on a train traveling from southern Russia to the occupied peninsula.

Russian President Vladimir Putin inaugurated the bridge in 2018, and since then it has played a crucial role in his military operation by allowing Russian supplies to reach Russian forces engaged in southern Ukraine.

Moscow's probe on the Russia Crimea Bridge Explosion was brushed off by a top Ukrainian official.

Ukraine's state-run media Suspline said that Andriy Yusov, a spokesman for the Ukrainian interior ministry, said that the FSB and Investigative Committee's efforts were "nonsense." He also depicted the two as "fake structures" serving Putin's leadership, so he prompted not to remark on their subsequent declarations.

Russia Pounds Ukrainian Cities with Missile Attacks

The Russian army retaliated with missile attacks on Ukrainian cities and power supplies on Monday. At least 19 people were killed and scores more were injured across Ukraine, including the capital of Kyiv, on a single day.

Read Also: Former Russian President Ominously Warns Kiev Regime To Receive More Retaliatory Strikes 

Russian President Vladimir Putin has warned that his country will respond "severely" to any future aggression from Ukraine.

Ukrainian military leader General Valeriy Zaluzhnyi revealed that out of 75 missiles fired, 41 were intercepted by the country's air defenses.

On Tuesday, Ukrainian President Volodymyr Zelenskyy asked the G7 for increased air defense system support as Russia Ukraine war continues.

The United Kingdom, Canada, France, Germany, Italy, Japan, the United States, and the United Kingdom committed to delivering financial, humanitarian, military, and legal aid to Ukraine "for as long as it takes."

Alarming Development on Zaporizhzhia Nuclear Plant

In other news, the director of the UN's nuclear watchdog said it was "very alarming" that Ukraine's largest nuclear facility, surrounded by Russian forces, lost all power from the outside on Wednesday.

AP News reported that International Atomic Energy Agency Director-General Rafael Grossi met with Vladimir Putin and reported that IAEA monitors at Europe's largest nuclear power facility, the Zaporizhzhia Nuclear Power Plant, had reported an interruption in external power and that backup diesel generators were keeping nuclear safety and security equipment operational.

Grossi said on Twitter that the incident is a "deeply worrying development," emphasizing the need to ensure "nuclear safety and security protection" in the area surrounding the facility.

Related Article: NATO Chief Urges for More Weapons to Ukraine as Zelensky Calls for New Sanctions Against Russia Following Missile Strikes