The first regiment of Russia’s advanced S-500 air defense systems has been delivered to a military unit guarding the airspace of the Russian capital Moscow, a source close to the Russian Defense Ministry has told TASS.

"The first regiment of the S-500 air defense systems has entered service with a unit, whose combat duty is to guard and defend the airspace above the capital of the country," he said, without specifying the military unit and the date when the systems entered service.

The airspace above the Russian capital and the Central Industrial District is guarded by the 15th Aerospace Forces Army (Special Purpose).

According to the source, the second S-500 regiment will be handed over to the Russian troops in the first half of 2022. The source added that it was a "long-term contract."

Deputy Prime Minister Yuri Borisov said on September 16 the latest S-500 Prometey air defense system had completed trials and the first launchers were supplied to the Russian armed forces. On July 20, the Defense Ministry reported that it had been tested against a high-speed ballistic target at the Kapustin Yar testing range in southern Russia.