Traffic on the key bridge connecting Crimea to Russia’s mainland has been halted after one of its sections was blown up in what Russian officials said was a Ukrainian attack that also killed a married couple and injured their daughter.

Russia’s National Anti-Terrorist Committee said that the attack on the Crimean Bridge had been staged by the Ukrainian special services and involved two sea drones.

Ukrainian officials did not claim responsibility for the attack, which is the second major strike on the bridge since October, when a truck bomb blew up two of its sections.

Natalia Humeniuk, a spokeswoman for the Ukrainian military’s Southern Command, said the explosions on the bridge could be a Russian provocation, but Ukrainian Ukrainska Pravda and RBC Ukraine news outlets said the attack was planned jointly by the Security Service of Ukraine (SBU) and the Ukrainian Navy and involved sea drones.

Kyiv did not initially acknowledge responsibility for October’s bombing, but a senior Ukrainian official did eventually confirm it.

The bridge is a key artery for supplying Crimea, which serves as a major hub for Russia’s war in Ukraine.

The attack on the bridge comes as Ukrainian forces are trying to press a counter-offensive in several sections of the front line.

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.

The Belgorod regional governor Vyacheslav Gladkov said the attack killed a married couple from the region, while their daughter was taken to hospital with serious injuries.

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

The damage appeared less serious than in October’s attack, which took months to repair.

Rail traffic resumed later on Monday morning after being halted for about six hours, and authorities said they were considering plans to use the undamaged road section of the bridge for traffic traveling in both directions.

The 12-mile bridge, the longest in Europe, opened in 2018 and is the main land connection between Russia and the Crimean peninsula.

Andriy Yusov, a spokesman for Ukraine’s military intelligence department, declined to comment on the incident but said: “The peninsula is used by the Russians as a large logistical hub for moving forces and assets deep into the territory of Ukraine. Of course, any logistical problems are additional complications for the occupiers.”

The Security Service of Ukraine posted a redacted version of a popular lullaby, tweaked to say that the bridge “went to sleep again”.