(CNN) Moscow is putting on a huge show of force in Crimea, a little over two years after Russia annexed the territory.

It is staging war games on land, air and sea in maneuvers called Kavkaz 2016, across Russia's entire southern military district on the border of Ukraine.

Russia's military jets and navy ships take part in military exercises in Crimea on September 9, 2016.

CNN's correspondent at the Opuk military base in Crimea, Fred Pleitgen, says the aim is clear.

"Russia is sending a very clear message with these large scale and very complex drills. Their forces are entrenched in Crimea and ready to fight at any time," he said.

"What they do in these military drills is simulate an invasion of Crimea, [and] they simulate their forces fighting off that invasion."