Ukraine's security service (SBU) has quickly claimed responsibility, describing that this time it was an underwater explosive attack, possibly facilitated with an unmanned submarine, which left the structure which goes from the Russian city of Krasnodar in the east to Kerch in Crimea "in disrepair".

Video was soon after published of the explosion of what the SBU called the "badly damaged" bridge after support columns were blown up.

"The Security Service of Ukraine carried out a new unique special operation and struck the Crimean Bridge for the third time – this time underwater!" the SBU declared on Telegram.

"Today, at 4:44 a.m., without any civilian casualties, the first explosive device was detonated," the statement said. "The underwater support pillars were severely damaged at the seabed level — aided by the equivalent of 1,100 kg of TNT. As a result, the bridge is effectively in an emergency condition."