Russia has vastly enhanced its military capabilities in Crimea since annexing the peninsula, turning it into a "power projection platform," a senior NATO general was reported Monday as saying.

"What we've seen is easy to describe as the militarisation of Crimea," the alliance's top commander for Europe, General Philip Breedlove, said in an interview with Ukrainian channel 1+1.

"They've brought an air capability, they've increased their capability to project sea power from there," he said.

"We see very capable surface-to-air defense systems that range about 40 percent of the Black Sea and we've seen very sophisticated missile defense systems that range almost the entire Black Sea."

"Crimea has become very much a power projection platform," he said in an interview broadcast in Ukrainian on Sunday evening, of which AFP has obtained the original English version.

Russia annexed Crimea after deploying soldiers to the peninsula in late February 2014. The troops took control of the territory, seizing Ukrainian ships and military bases, while the authorities organised a referendum that demonstrated overwhelming support for the province joining Russia.

Although Putin initially denied that any Russian troops were involved in the takeover, he later conceded their presence.

On Sunday, in a preview of a film about Crimea on state channel Rossiya-1 Putin revealed that he ordered his security chiefs to "return" the peninsula to Russian rule as early as February 23.

Ukraine's government, which has also been battling a bloody pro-Russian insurgency in the east of the country, accuses Moscow of massing forces in Crimea across the de-facto border from its Kherson region.