Traffic on the single bridge that links Russia to Moscow-annexed Crimea and serves as a key supply route for the Kremlin’s forces in the war with Ukraine came to a standstill on Monday after one of its sections was blown up, killing a couple and wounding their daughter.

The RBC Ukraine news agency reported that explosions were heard on the bridge, with Russian military bloggers reporting two strikes.

The bridge is a crucial supply route for Russian forces in Ukraine.

Here is what we know about the bridge and the incident.

What happened on the bridge?

The bridge suffered damage, according to Russian authorities, after one of its sections was blown up, killing two people and wounding a child.

Russia’s National Antiterrorism Committee said the strike on the 19km (12-mile) Kerch Bridge was carried out by two Ukrainian sea drones.

Grey Zone, a heavily followed Telegram channel affiliated with the Wagner mercenary group, reported that there were two strikes on the bridge at 3:04am (00:04 GMT) and 3:20am (00:20 GMT) on Monday.

A video posted by Crimea 24 online news channel showed a section of the bridge tilted and hanging down, but there was no indication any portion had fallen into the water.

Russian authorities said the attack did not affect the piers but damaged the decking in a section of one of the two road links.

Rail traffic resumed later on Monday morning after being halted for about six hours.

Who was responsible for the attack on the Kerch Bridge?

That remains unclear.

Russian officials blamed the attack on Ukraine, but Kyiv did not openly admit it.

Natalia Humeniuk, a spokesperson for the Ukrainian military’s Southern Command, said the explosions could be a Russian provocation.

But RBC Ukraine and another Ukrainian news outlet Ukrainska Pravda said the attack was planned jointly by the Security Service of Ukraine (SBU) and the Ukrainian navy, and involved sea drones.

In what appeared to be an indirect acknowledgement of Ukraine’s involvement, SBU spokesperson Artem Degtyarenko said details of what happened would be revealed after Ukraine has won the war.

Why does the bridge matter?

The bridge is crucial for the supply of fuel, food and other products to Crimea, where the port of Sevastopol is the historic home base of Russia’s Black Sea Fleet.

The peninsula has enough supplies of fuel, food and factory goods, acting Industrial Politics Minister Yelena Elekchyan said.

The bridge also became a major supply route for Russian forces after Moscow invaded Ukraine last year, sending forces from Crimea to seize most of southern Ukraine’s Kherson region and some of the adjoining Zaporizhia province.

Is this the first attack on this bridge?

In October last year, the bridge was damaged in a powerful blast, with Russian officials saying the explosion was caused by a truck that blew up while crossing the bridge.

Three people were killed.

Putin branded that blast a “terrorist attack” orchestrated by Ukrainian security services and ordered a wave of retaliatory strikes on Ukrainian cities, including the capital, Kyiv.

Months later, Ukraine’s President Volodymyr Zelenskyy claimed only indirectly that his country was responsible for the attack, listing the bridge as one of his army’s “successes” in 2022.

Crimea and the Russian link

The 19km (12-mile) bridge over the Kerch Strait is the only direct link between the transport network of Russia and the Crimean Peninsula, which Moscow annexed from Ukraine in 2014.

The bridge was a flagship project for Putin, who opened it himself for road traffic with great fanfare by driving a truck across in 2018.

It consists of a separate roadway and railway, both supported by concrete stilts, which give way to a wider span held by steel arches at the point where ships pass between the Black Sea and the smaller Azov Sea.

The structure was built at a reported cost of $3.6bn by a firm belonging to Arkady Rotenberg, a close ally and former judo partner of Putin.