Russia has launched major military exercises in Crimea on Thursday under the personal supervision of Defence Minister Sergei Shoigu as Russia’s troop buildup near Ukraine raises alarm in the West.

Iran Press/Europe: Russia’s navy, aerospace forces, airborne troops, and air defense forces are expected to perform airstrikes, deploy cruise missiles, and use drones during the snap readiness maneuvers.

“More than 10,000 troops, 1,200 weapons units, and more than 40 warships and 20 support vessels are involved in the active phase,” Russia’s state-run RIA Novosti news agency quoted the military as saying.

Russian Defense Minister Sergei Shoigu has arrived in Crimea, which Moscow annexed from Ukraine in 2014 and has begun militarizing in the years since, to oversee the snap drills.

Russia’s Defense Ministry previously said it blocked flights for April 20-24 naval drills and closed off navigation to foreign ships from mid-April until the end of October.

The Russian military has announced some 4,000 drills throughout the month of April for so-called “winter period control checks” across the country’s 11 timezones.

The European Union estimates that Russia has amassed more than 100,000 troops near Ukraine and in Crimea, which observers call the largest troop buildup since the eastern Ukrainian conflict first broke out in 2014. 

The US Federal Aviation Administration (FAA) over the weekend issued a Notices to Airmen (NOTAM) alert warning US airlines to exercise “extreme caution” over areas near the Russia-Ukraine border as tensions surge over Russia’s military buildup and renewed clashes in eastern Ukraine.