An attack before dawn Monday damaged part of a bridge linking Russia to Moscow-annexed Crimea that is a key supply route for Kremlin forces in the war with Ukraine, forcing the span’s temporary closure for a second time in less than a year. Two people were killed and their daughter was injured.

Vehicle traffic on the Kerch Bridge came to a standstill, while rail traffic across the 19-kilometer (12-mile) span also was halted for about six hours.

The strike was carried out by two Ukrainian maritime drones, Russia’s National Anti-Terrorist Committee said.

Ukrainian officials were coy about taking responsibility, as they have been in past strikes. But in what appeared to be a tacit acknowledgment, Ukrainian Security Service spokesman Artem Degtyarenko said in a statement that his agency would reveal details of how the “bang” was organized after Kyiv has won the war.

The bridge previously was attacked in October, when a truck bomb blew up two of its sections and required months of repair. Moscow decried that assault as an act of terrorism and retaliated by bombarding Ukraine’s civilian infrastructure, targeting the country’s power grid over the winter.

In Monday's blast, the Ukrainian news portal RBK-Ukraina cited a security services source as saying it was carried out by what it called floating drones. A deputy prime minister, Mykhailo Fedorov, later said on the Telegram messaging service that “today, the Crimea bridge was torn apart by sea drones,” but it was not clear if he was making an official confirmation or referring to earlier reports.

Hours after Monday's attack, video from Russian authorities showed crews picking up debris from the deck of the bridge, a section of which appeared to be sloping to one side, and a damaged black sedan with its passenger door open.

Russian Deputy Prime Minister Marat Khusnullin said authorities were inspecting the damage before determining how long it will take to repair.

The Kerch Bridge is a conspicuous symbol of Moscow’s claims on Crimea and an essential land link to the peninsula, which Russia illegally annexed in 2014. The $3.6 billion bridge is the longest in Europe and is crucial for Russia’s military operations in southern Ukraine in the nearly 17-month-old war.

The bridge attack comes as Ukrainian forces are pressing a counteroffensive in several sections of the front line. 

Russian media identified the dead as Alexei and Natalia Kulik, who were traveling to Crimea for a summer vacation. The 40-year-old Kulik was a truck driver and his 36-year-old wife was a municipal education worker. Their 14-year-old daughter suffered chest and brain injuries.

Russian authorities said the attack didn't affect the bridge's piers but damaged the deck on one of two road links. The damage appeared less serious than in October's attack.