Crimea is a peninsula located on the northern coast of the Black Sea. With the collapse of the Soviet Union in 1991, Crimea became part of the newly independent Ukraine, leading to tensions with neighboring Russia.
In 1954, Crimea was transferred to the Ukrainian Soviet Socialist Republic as a symbolic gesture by Soviet leader Nikita Khrushchev. Following the breakup of the Soviet Union in 1991, Crimea became part of the independent Ukraine. Russia's Black Sea Fleet is stationed in Sevastopol and the southern tip of the peninsula continues to be a Russian stronghold in the region. Throughout the last decades tensions between the two neighbors have occasionally flared, but nothing like the escalation and mobilization of troops in March 2014.
A Russian investigative newspaper says the Kremlin was presented with a plan to annex the Crimea and large parts of eastern Ukraine before the downfall of former President Viktor Yanukovich. The Novaya Gazeta newspaper says Russian oligarch Konstantin Malofeev and his associates could have been behind the plan.
Tensions are high ahead of four-way peace talks in Minsk, aimed at de-escalating the Ukraine crisis. With both sides launching new offensives to gain territory in the east, separatists are reported to have surrounded thousands of government troops at Debaltseve.
Lawmakers in Russia are considering a proposal to condemn Germany's 1990 reunification, labeling it an "annexation" of the East by the West. It's thought to be Moscow's answer to condemnation of its takeover of Crimea.
About 30 people have been killed in the eastern Ukrainian city of Mariupol as fighting escalated to the worst level in months. Pro-Russia separatists had announced they were launching an offensive on the strategic city.