Ukraine said it shot down a Russian strategic bomber in combat for the first time since Russia invaded, after the plane launched a missile strike that killed at least seven people.

The Tu-22M3, a Soviet-era design, was downed some 300 kilometers inside Russia, Ukraine’s GUR military intelligence agency said on its website. Ukrainian authorities didn’t specify which weapon brought down the plane. Russian news agencies said at least one of the pilots was killed and quoted the Defense Ministry as blaming a technical fault.

Losing the plane signals a new vulnerability for Russian President Vladimir Putin’s military, which relies on Cold War-era bombers as the main tool in its missile campaign against Ukraine. The supersonic Tu-22 can launch strikes from deep within Russia, leaving it effectively untouchable for Ukraine’s air defenses.