evidence: Crimea is a centre of pro-Russian sentiment, which can spill into separatism. The region - a peninsula on Ukraine's Black Sea coast - has 2.3 million people, a majority of whom identify themselves as ethnic Russians and speak Russian. [...] Crimea is an autonomous republic within Ukraine, electing its own parliament, with a prime minister appointed with approval from Kiev. But now Crimean MPs have appointed a pro-Moscow leader, Sergei Aksyonov, who wants Crimea to unite with Russia, and has called the referendum.