Three Russian military pilots died after ejection seats were accidentally activated

Three Russian warplane pilots died Tuesday after their ejection seats were accidentally activated during preflight checks, the Russian military said.

The Russian Defense Ministry said the fatal accident occurred at a military airbase in the Kaluga region, about 90 miles southwest of Moscow.

The ministry also said the Tu-22M3 long-range bomber crew was making preparations for a training mission when the pilots were ejected from the plane as a result of a faulty ejection system, according to the Associated Press. The ministry reported that the parachutes could not be opened because the altitude was not sufficient. The three crew members died of injuries.

An official investigation into the deaths of the pilots has begun.

The warplane is a Tu-22M3, a supersonic twin-engine long-range bomber, capable of carrying nuclear weapons.