Ukraine struck Russia’s Engels strategic bomber base on Thursday with drones, triggering a major blast and fire about 700 km (435 miles) from the front lines of the war, Russian officials and media reported.

Unverified video on Russian Telegram channels showed a major blast spreading out from the airfield, wrecking nearby cottages. Russia’s defence ministry said air defences had shot down 132 Ukrainian drones over Russian regions.

Video verified by Reuters based on the position and shape of buildings showed a plume of smoke rising above damaged cottages.

The base in Engels, which dates back to early Soviet times, hosts Russia’s Tupolev Tu-160 nuclear-capable heavy strategic bombers, known unofficially as White Swans.

Roman Busargin, the governor of Saratov, said there had been a Ukrainian drone attack on the city of Engels that had left an airfield on fire, and that nearby residents had been evacuated. He did not specifically mention the Engels base, but it is the main airfield in the area.

Engels district head Maxim Leonov said that a local state of emergency had been declared but gave few details. Reuters was unable to independently confirm what had taken place at the airfield.

Ukraine has conducted previous attacks on the Engels air base dating back to December 2022. In January it claimed to have struck an oil depot serving the base, causing a huge fire that took five days to put out.

A Ukrainian security source said at the time that a drone attack had struck a storage facility holding guided bombs and missiles at the Engels base.