“The aircraft has crashed near Marinovka Air Base outside Volgograd. There were two crew members on board, of whose fate is so far unknown,” the source said.
A search for the aircraft is underway.
The source added that the bomber crashed just 7 kilometers (4.3 miles) from the runway.
The Sukhoi Su-24 twin-engine frontline bomber was developed in the Soviet Union. The modified version, Su-24M, entered service in 1983 and is still in use by some former Soviet states. In 2010, the Russian Air Force decided to replace its Su-24s with modern Su-34s.