Russia said two Ukrainian drones caused explosions that damaged its flagship bridge to Crimea, killing two people and causing the suspension of road and rail traffic.

“Two Ukrainian unmanned surface vehicles attacked the Crimean bridge” in the early hours of Monday, the National Antiterrorism Center said. The attack that damaged a section of the road bridge was carried out by “Ukrainian special services,” Russia’s Investigative Committee said in a statement.

State television showed part of the roadway had buckled on the giant bridge across the Kerch Strait that links Russia to Crimea. Two people died and a teenage girl was injured in a car on the bridge at the time of the attack, the Investigative Committee said.

The blasts occurred as the clock is ticking down on a deal permitting Black Sea grain exports from Ukraine. Russia indicated last week that it may withdraw at midnight from the agreement that was brokered by the United Nations and Turkey. President Vladimir Putin called construction of the 19-kilometer (12-mile) bridge a “historical mission” for Russia before it opened in 2018, four years after he annexed Crimea from Ukraine.

A massive blast ripped through the bridge last October, damaging one of its road spans and temporarily halting rail traffic that’s used to supply Russian forces in the peninsula and in southern Ukrainian areas facing a counteroffensive from Kyiv’s troops to reclaim the territories.

Putin blamed that attack on Kyiv and Russia later unleashed some of the most intense barrages of strikes against Ukraine since the first days of its February 2022 invasion.

Ukraine didn’t directly claim involvement in the latest attack, and earlier pointed the finger at Russia. “Since the issue of the future of the grain deal is on the agenda today, one can assume that the enemy is capable of using any provocations,” Ukrainian military spokeswoman Natalia Humenyuk said in televised comments.

The Russian Defense Ministry reported Sunday that seven drones and two underwater vehicles were destroyed in Crimea, accusing Ukraine of a “terrorist attack.”