Video shows mystery 'wave' under Crimea bridge just before it was blown up killing three: Speculation grows that Ukraine used a boat or explosive-laden drone - despite Russian claims of truck bomb - as attack threatens Putin's supply lines

Russia has blamed a truck bomb for the explosion which killed at least three people, but new footage suggests the attack could have been underwater. Videos show the explosion rocking the Kerch Bridge linking the peninsula with the Russian mainland - despite Russian claims the bridge was protected with a maximum-security operation which included attack dolphins. The attack could cut supplies to Putin's forces as Ukraine makes more advances in the south towards Kherson. A section of the bridge has collapsed into the sea and seven oil tankers on a train caught fire in the blast. Long fuel lines are already forming in Crimea, despite Russian claims to have enough supplies to last two weeks.