Ukraine launched a drone strike on Russia’s Engels strategic bomber base on Thursday, triggering a powerful explosion and fire nearly 700 km (435 miles) from the war’s front lines, according to Russian officials and media reports.

Unverified footage circulating on Russian Telegram channels depicted a massive blast engulfing the airfield and destroying nearby cottages. Russia’s defense ministry claimed to have intercepted 132 Ukrainian drones across various regions.

Video analysis by Reuters, based on building locations and structures, confirmed a plume of smoke rising over damaged homes in the area.

The Engels base, a relic from the early Soviet era, houses Russia’s Tupolev Tu-160 heavy strategic bombers, often referred to as "White Swans" and capable of carrying nuclear weapons.

Saratov Governor Roman Busargin confirmed an attack on Engels, stating that an airfield had caught fire and nearby residents were evacuated. While he did not explicitly mention the Engels base, it remains the primary airfield in the region.

Local Engels district head Maxim Leonov declared a state of emergency but provided few additional details. Reuters has not independently verified the extent of the damage at the airfield.

Ukraine has previously targeted the Engels air base, with attacks dating back to December 2022. In January, Kyiv claimed responsibility for striking an oil depot supplying the base, resulting in a massive fire that took five days to extinguish.

A Ukrainian security source previously stated that a drone attack had hit a storage facility at the base, damaging guided bombs and missiles.