Russia has completed rearming air defense forces in Crimea with its advanced S-400 Triumf surface-to-air missile systems, Russian officials confirmed at an annual Defense Ministry year end review meeting on Tuesday.

“This year, we have completed rearming air defense units stationed in Crimea with the S-400 Triumph systems. Today they are on combat duty, reliably protecting the airspace over the entire Crimean Peninsula,” the Commander of the Southern Military District, Colonel-General Alexander Dvornikov said, according to TASS. Russian commanders have touted the S-400 missiles' capabilities of engaging targets at a distance of 400km and at an altitude of up to 30km (though western analysts say the numbers are lower), and have lately widely publicized the new Crimean missile deployments following the Nov. 25 Kerch Strait incident.

File photo of S-400 system in Moscow, via RIA Novosti/Reuters

Early this month FOX published satellite photos which further confirmed newly deployed Russian S-400 surface-to-air missile batteries were being installed at the Dzhankoy airbase in Crimea.

The Fox report noted that the new S-400 deployment was already underway prior to spiking tensions between Moscow and Kiev over the Kerch Strait Ukrainian navel vessel seizures by Russia:

The intelligence report by ImageSat International indicates that the infrastructure for the S-400 battery was prepared in recent months, a long time before last weekend's naval encounters that sparked new tension between Russia and Ukraine.

But Russia has repeatedly publicized its build-up of forces in Crimea, which also includes tanks and increased military personnel, since the November incident and subsequent war of words.

Crimea's Russian military defenses have been bolstered with at least three S-400 systems since 2017, with the present deployment reinforcing these further, bringing the total number of systems to four.

Russia's military has called it a "combat" deployment toward "neutralizing possible threats". According to a statement by Commander Dvornikov on Tuesday:

For the purposes of neutralizing possible threats, the troops of the Southern Military District continued accomplishing their combat duty tasks to provide for air defense of Russia’s southern frontiers and protect its allies in the airspace in the troops’ entire zone of responsibility.

Russia first announced deployment of the additional S-400 missiles in late November, just days following the contentious encounter in the Kerch Strait, and while facing condemnation from the West.

At the time the Ukrainian foreign ministry issued a strong condemnation of the planned deployment, describing the development as "dangerous not only for Ukraine" but the whole Black Sea region. "The system's operational range is up to 400km so it places all literal states in the Black Sea region, including NATO members under the threat of an attack. We know that those missiles can be used also for ground targets," Olexiy Makeyev, the foreign ministry's political director said.

Makeyev claimed that from the time of Russia's annexing the Crimea in 2014, its military has brought in "new weapon systems including nuclear-capable aircraft and missiles as well as military personnel".

With advanced Russian defenses so deeply entrenched along the Black Sea, western countries like the UK and US — both of which have seriously mulled sending destroyers to the area — are unlikely to take steps toward escalation.