MOSCOW, June 8. /TASS/. Russia’s Defense Ministry has signed a three-year contract on receiving about 20 Sukhoi Su-34 frontline bombers, a source in the domestic defense industry told TASS on Monday.

"Last week, a contract was signed between the Defense Ministry and the Sukhoi Aircraft Company on building about 20 Su-34 frontline bombers," the source said.

The contract involves standard Su-34 aircraft with certain alterations based on the experience of the operation of several dozen bombers of this type earlier purchased for the troops, the source said.

A contract on the purchase of upgraded Su-34M planes "is expected to be signed in 2021," the source added.

The Su-34 multirole supersonic fighter-bomber is designated to effectively strike enemy ground and air targets day and night in any weather conditions.

The Su-34 carries long-range air-to-surface and air-to-air missile armament with the multi-channel employment capability. The Su-34 has an operating range of 4,000 km, can develop a maximum speed of 1,900 km/h and is capable of carrying a weapon payload of up to 8 tonnes. The Su-34 is half as noisy as earlier models.