Authorities in Western Siberia’s Tyumen region said they downed three drones near an industrial site on Monday evening in what may be the furthest Ukrainian drone incursion reported inside Russian territory since the start of the war.

Tyumen residents posted videos online showing fire trucks and ambulances rushing toward the Antipinsky oil refinery, one of the region’s largest, with a processing capacity of 9 million tons of crude per year. Local Telegram news channels reported there being at least two explosions and mobile network disruptions in the area, located roughly 2,000 kilometers (1,240 miles) from the Ukrainian border.

Regional authorities said that emergency crews were initially dispatched to an industrial site in Antipino after reports of explosions and fire, but added that no blaze was found. Less than 30 minutes later, they said three drones were “detected and neutralized on the premises of an enterprise.”

“A prompt response from emergency services prevented a detonation. There were no casualties, explosions or fires. All enterprises in the area continue to operate normally,” the Tyumen government press service said without specifying who was behind the drone incursion.