The Crimean Bridge, which links the annexed peninsula to mainland Russia, was hit by two strikes early Monday in an attack a Ukrainian security official told CNN Kyiv was responsible for.

The crossing is a vital artery for supplying Russia's ongoing war on Ukraine, allowing people and goods to flow into the Ukrainian territories that Moscow has occupied in the south and east of the country.

Also known as the Kerch Bridge, it holds personal value for Russian President Vladimir Putin. In the Kremlin narrative it marks the "reunification" of Crimea with the Russian mainland.

Monday's attack on the crossing was the second since Putin launched his full-scale invasion of Ukraine -- and Kyiv has reiterated that it hopes to reclaim the peninsula in its ongoing counteroffensive.

Here's what you need to know:

Why is the bridge so important to Russia?

The Kerch Bridge is strategically important because it links Russia's Krasnodar region with Crimea, which was illegally annexed by Russia from Ukraine in 2014.

It also has huge symbolic importance for Russia, which built the 12-mile bridge -- the longest in Europe -- at a cost of around $3.7 billion. It was the physical expression of Putin's objective to take over Ukraine and bind it to Russia forever.

The day it opened, Putin led a triumphant convoy over the bridge. Ukrainians revile the bridge, which stands as a reminder of Russian occupation.

In October, the bridge was partially destroyed when a fuel tanker exploded and damaged a large section of the road. The Kremlin was quick to blame Kyiv for that explosion, and Putin alleged that it was an act of "sabotage" by Ukrainian security services. Moscow was quick to repair the bridge after the explosion last year.

What does Russia use the bridge for in the war?

The bridge is a critical pipeline for providing Crimea with both its daily needs and supplies for the military, in addition to fuel and goods for civilians. Russian military convoys have regularly used the bridge to aid their full-scale invasion of Ukraine -- carrying vehicles, armor and fuel.

If the Russian military's use of the crossing is hampered, its supply lines to forces in southern Ukraine would become more tenuous.

Russia has used the Crimean railroads to ferry supplies to forces in Kherson, and several rail hubs in both Crimea and Kherson have been attacked by long-range Ukrainian rockets. Rail traffic across the Crimea bridge is continuing to operate on Monday, albeit with delays, according to video on social media, a Russian official and Russian state media.

Ukraine's counteroffensive has been advancing into the Kherson region, which is just north of Crimea. The Ukrainian military's General Staff said last week that in the south of Ukraine, in particular in the Zaporizhzhia and Kherson directions, Russian forces are focusing their main efforts on preventing further advance of Ukrainian troops.

What is the status of the bridge?

A widely circulating video, which appears to have been captured this morning from a train passing on the parallel rail bridge, shows significant damage to one of the bridge's road spans.

"The railroad track was not damaged by the strike," Vladimir Konstantinov, head of the State Council of the Republic of Crimea, said on his Telegram channel. Russian state media RIA Novosti and TASS report that rail traffic is continuing to operate with delays.

Prominent Russian military blogger Boris Rozhin said on Monday morning that ferries and other large landing ships will transport cars that are now unable to cross the bridge, adding that he expects repairs to take some time.

What is the Kremlin saying?

The Russian government on Monday said that two Ukrainian seaborne drones were responsible for the bridge attack, though it did not provide evidence for that allegation.

The Kremlin has also opened an official investigation into what the Russian Investigative Committee calls "a terrorist act committed by the special services of Ukraine."

Putin has been briefed on the strike, Kremlin spokesperson Dmitry Peskov told reporters on Monday.

Meanwhile, Russia's Deputy Prime Minister Marat Khusnullin will travel to Crimea on Monday to assess the situation.

What is Ukraine saying?

A source in Ukraine's Security Service (SBU) told CNN the attack on the bridge was a joint operation of the SBU and Ukraine's naval forces.

The source spoke to CNN on condition of anonymity because they had not received authorization to speak on the record.

Earlier on Monday, a Representative of the Defense Intelligence of Ukraine Andrii Yusov told Ukraine's public broadcaster that the destruction of part of the Crimean bridge could create logistical difficulties for Russian forces who have been using it "as a major logistics hub for moving forces and resources deep into the territory of Ukraine."

"Of course, any logistical problems are additional complications for the occupiers, which create potential advantages for the Ukrainian defense forces," Yusov noted.