The bridge is both highly symbolic to Russia and an important logistical supply route.
Its location allows supplies to flow into Russian-occupied Ukraine via Crimea.
Also known as the Crimean Bridge, the Kerch Bridge is 12 miles long and was built by Russia after it annexed Crimea.
The multibillion-dollar contract for the bridge was first awarded in 2015, with the bridge eventually opened by Vladimir Putin in May 2018.
The attack on the bridge marks another humiliating setback for Moscow, following weeks of battlefield reversals as Ukrainian forces push back at the frontlines.