Stalin accused the Tatars of collaborating with the German occupiers and deported them to Central Asia and Siberia in 1944. Many did not survive.

Only as the Soviet Union collapsed in 1991 were they allowed to return. By the time over a quarter of a million did so in the early 1990s, it was to an independent Ukraine where they faced very high unemployment and extremely poor housing conditions.

There were persistent tensions and protests over land rights, and allocation of land to Crimean Tatars was a contentious issue.

After Ukrainian independence, political figures from the local Russian community sought to assert sovereignty and strengthen ties with Russia through a series of moves declared unconstitutional by the Ukrainian government.

The 1996 Ukrainian constitution stipulated that Crimea would have autonomous republic status, but insisted that Crimean legislation must be in keeping with that of Ukraine.

Crimea has its own parliament and government with powers over agriculture, public infrastructure and tourism.

The Crimean Tatars have their own unofficial parliament, the Mejlis, which states its purpose as being to promote the rights and interests of the Crimean Tatars.

The port of Sevastopol is a major naval base and has been home to the Black Sea Fleet since 1783. Following the collapse of the USSR, the fleet was divided up between Russia and Ukraine.

The presence of the Russian fleet in Sevastopol was a focus of tension between Russia and Ukraine. In 2008, Ukraine - then under the pro-Western President Viktor Yushchenko - demanded that Moscow not use the Black Sea Fleet during the its war with Georgia.

Both countries had agreed to allow the Russian fleet to stay until 2017, but after the election of the pro-Russian Viktor Yanukovych as president in 2010, Ukraine agreed to extend the lease by 25 years beyond 2017, in return for cheaper Russian gas.

In 2022, President Volodymyr Zelensky cemented Ukraine's goal of liberating all its territories, including Crimea, in a peace formula he presented at the G20 summit in Bali.

In 2022 and 2023, the strategic Kerch bridge - actually a pair of bridges - which link Crimea to Russia's Taman peninsula across the Sea of Azov came under repeated Ukrainian attack.

It is one of the key ways Moscow can reinforce its troops in Crimea and the southern Kherson region and logistics hubs across Russian-occupied territory have been repeatedly hit using long-range weapons supplied by Ukraine's Western backers.