Russia annexed the Black Sea peninsula from Ukraine in 2014, a move that resulted in Western economic sanctions. The first S-400 air-defense system was installed in the territory last year and assumed combat duty in January 2017.

Russia reportedly plans to move a second S-400 anti-aircraft missile system to the annexed Crimean peninsula in the coming months.

The latest S-400 system performed shooting drills for “operational readiness” at a missile test range in Russia’s southern Astrakhan region, a senior military official said Thursday.

Vadim Astafyev, Russia’s Southern Military District spokesman, told the state-run TASS news agency that the missiles would be placed on combat duty in Crimea "soon."

Astafyev did not specify the date of the S-400’s planned deployment in the disputed territory. Earlier this year, the Tass agency reported that that the anti-aircraft system would be deployed in Crimea in the latter half of 2017 and put on combat duty in February 2018.