FOOTAGE OF THE TRUCK THAT WAS DETONATED ON THE CRIMEAN BRIDGE

source: https://www.bitchute.com/video/DJRRr39LXFvy/

Russia officially states that Ukraine is responsible. This means Russia will have to respond militarily or face grave consequences from their citizens. Russian politicians, including Medvedev and Putin himself made it clear that they will strike Ukrainian decision centres if the Crimean bridge is touched.
Russia could have easily passed this off as an accident, but they chose not to. This could mean they are ready to escalate & have it seen as retaliation by their media; rather than an attack.