The Kerch bridge from Russia to Crimea, a key supply route for Russian troops, opened by Vladimir Putin in 2018, has been hit this morning by a huge explosion.

The explosion took place before 6am on Saturday while a train was crossing the bridge. Images from the place showed a burning fire engulfing at least two railway carriages from a train on the bridge and one half of the parallel road bridge collapsed into the Kerch Strait.

Today at 06:07 (03.07 GMT) on the road part of the Crimean bridge from the side of the Taman Peninsula, a truck was blown up, which caused the ignition of seven fuel tanks of a railway train heading towards the Crimean peninsula.

Russian state agency RIA Novosti, quoting the National Anti-Terrorism Committee (NAC)

Some footage shared on Russian Telegram channels appeared to show the moment of the explosion with two vehicles, a truck and a car, at the centre of the blast, although it was unclear whether either was responsible or simply caught up in the detonation. There is no obvious sign of a missile strike in the first images to emerge, leading some to suggest the attack might have been a spectacular act of sabotage.

The big infrastructure is a symbol of the Kremlin’s occupation of the southern Ukrainian peninsula and one of Vladimir Putin’s prestige projects. It was built by Russia after its invasion and annexation of Crimea in 2014. The blast on the bridge came a day after Putin marked his 70th birthday.

The crossing is more than 100 miles from Ukrainian-held territory and Russia had maintained it was safe despite the fighting in Ukraine but had threatened Kyiv with reprisals if it was attacked.

The bridge is an important logistical supply route for Russian forces in Crimea and in southern Russian-occupied Ukraine. The damage to the railway line in particular leaves Russian forces in the south with a single railway supply line, between Krasnodar and Melitopol, now within range of Ukraine attacks.

Mykhailo Podolyak, adviser to the Ukrainian president, wrote on Twitter: “Crimea, the bridge, the beginning. Everything illegal must be destroyed, everything stolen must be returned to Ukraine, everything belonging to the Russian occupation must be expelled.”

In the immediate aftermath of the explosion reports emerged of residents in the Crimea rushing to petrol stations anxious about fuel shortages. There are no reports of casualties, so far.