Ukraine crisis timeline
The toppling of President Viktor Yanukovych in Ukraine has led to escalating tensions, with fears of a Russian takeover of the Crimean peninsula.
The crisis began in November with Mr Yanukovych's decision to pull out of an agreement on closer ties with the EU, and led to increasingly violent protests in the capital, Kiev.
BBC News charts the turbulent moments in Ukraine's recent history:
13 March: Ukraine's parliament votes to create a 60,00 strong National Guard force to defend the country.
12 March: In a show of support, US President Barack Obama welcomes Ukraine's interim Prime Minister Arseniy Yatsenyuk to the White House and pledges to stand with Ukraine.
11 March: The European commission offers Ukraine trade incentives worth nearly 500m euros ($694m; £417m) to try to shore up its flagging economy, and the Ukrainian parliament asks the US and UK - as guarantors of the security pledges given to Ukraine in 1994 - to use all measures, including military, to stop Russia's aggression.
10 March: Armed men seize a military hospital in Simferopol as UK Prime Minister David Cameron warns Russia could face targeted sanctions "within days".
9 March: Ukrainian PM Yatsenyuk pledges not to give a "single centimetre" of Ukraine's land to Russia. Tens of thousands of people hold rival pro-unity and pro-Russian rallies across Ukraine, with pro-Russia demonstrators beating up their opponents in Sevastopol.
8 March: The US and France warn of "new measures" against Russia if it does not withdraw its forces from Ukraine. Warning shots are fired at monitors from the Organization for Security and Co-operation in Europe [OSCE] as they are turned back and prevented from entering Crimea again. Russian Foreign Minister Sergei Lavrov says the crisis was "created artificially for purely geopolitical reasons".
7 March: Russia says it will support Crimea if the region votes to leave Ukraine. Russia's state gas company Gazprom warns Kiev that its gas supply might be cut off. OSCE monitors are prevented from crossing into Crimea by armed men. Ukraine's team at the Paralympic Games in Sochi protest against Russia's actions by sending just one athlete to the opening ceremony.
6 March: Crimea's parliament asks to join Russia and will put the decision to a referendum on 16 March.
5 March: Talks in Paris between Russia and Western powers end without agreement. Russian Foreign Minister Sergei Lavrov refuses to meet his new Ukrainian counterpart. The UN envoy to Crimea Robert Serry cuts short his mission there after being threatened by armed men.
4 March: Russian President Vladimir Putin breaks silence, denying Russian troops have besieged Ukrainian forces in Crimea, asserting they are self-defence forces. Ukrainian installations are surrounded by soldiers apparently in Russian uniforms who prevent a Ukrainian force from retaking Belbek airbase, near Sevastopol.
3 March: "Black Monday" on Russian stock markets as reports suggest Russia's military had issued a deadline for Ukrainian forces in Crimea to surrender. The reports are later denied. Russia's UN envoy says toppled President Yanukovych had asked the Russian president in writing for use of force.
2 March: Ukraine's interim PM Yatsenyuk says Russia has effectively declared war. US says Russia is in control of Crimea. Ukraine's newly appointed naval chief defects.
1 March: Russian parliament approves President Vladimir Putin's request to use Russian forces in Ukraine. In Kiev, acting President Olexander Turchynov puts the army on full alert. Large pro-Russian rallies are held in several Ukrainian cities outside Crimea, including the second-biggest city Kharkiv. The West reacts with alarm: US President Barack Obama tells Mr Putin in 90-minute telephone conversation to pull forces back to bases. Mr Putin says Moscow has right to protect its interests and those of Russian-speakers in Ukraine.
27-28 February: Pro-Russian gunmen seize key buildings in the Crimean capital, Simferopol. Unidentified gunmen in combat uniforms appear outside Crimea's main airports, sparking fears of Russian military intervention. At his first news conference since fleeing Ukraine, Viktor Yanukovych, now in southern Russia, insists he remains president and opposes military intervention or division of Ukraine.
23-26 February: Parliament names speaker Olexander Turchynov as interim president. An arrest warrant is issued for Mr Yanukovych, and the acting president warns of the dangers of separatism. Members of the proposed new government appear before demonstrators, with Arseniy Yatsenyuk nominated prime minister. The elite Berkut police unit, blamed for deaths of protesters, is disbanded. Rival protests are held in Crimea.
22 February: Events move quickly
- President Yanukovych disappears - reports say he has left for Kharkiv in the north-east
- Protesters take control of presidential administration buildings without resistance
- Opposition leaders call for elections on 25 May; Parliament votes to remove president from power with elections set for 25 May
- Mr Yanukovych appears on TV to insist in a recorded message that he is lawfully elected president and to denounce "coup"
- His arch-rival Yulia Tymoshenko, jailed for seven years in 2011, is freed and travels from Kharkiv to address Kiev crowds
21 February: President Yanukovych signs compromise deal with opposition leaders, brokered by French, Polish and German foreign ministers. A new national unity government is to be formed with constitutional changes handing powers back to parliament and early elections, held by December. Sporadic violence continues and protesters remain defiant.
20 February: As truce breaks down, Kiev sees its worst day of violence for almost 70 years. At least 88 people are killed in 48 hours of bloodshed. Video shows uniformed snipers firing at protesters holding makeshift shields. Three European Union foreign ministers fly in to try to broker a deal; Russia announces it is sending an envoy.
18 February: Clashes erupt, with reasons unclear: 18 dead, including seven police, and hundreds more wounded. Some 25,000 protesters are encircled in Independence Square.
14-16 February: All 234 protesters arrested since December are released. Kiev city hall, occupied since 1 December, is abandoned by demonstrators, along with other public buildings in regions.
28-29 January: Prime Minister Mykola Azarov resigns and parliament annuls the anti-protest law. Parliament passes amnesty bill promising to drop charges against all those arrested in unrest if protesters leave government buildings. Opposition rejects conditions.
16-23 January: Parliament passes restrictive anti-protest laws, Days later two people die of gunshot wounds as clashes turn deadly for first time. Third death reported as the body of high-profile activist Yuriy Verbytsky is found. Protesters begin storming regional government offices in western Ukraine.
17 December: Russian President Vladimir Putin throws President Yanukovych an economic lifeline, agreeing to buy $15bn of Ukrainian debt and reduce the price of Russian gas supplies by about a third.
Early December: Protesters occupy Kiev city hall and Independence Square in dramatic style, turning it into a tent city. Biggest demonstration yet sees 800,000 people attend demonstration in Kiev.
Late November: Protests gather pace, as 100,000 people attend demonstration in Kiev, the largest in Ukraine since the Orange Revolution. Police launch first raid on protesters, arresting 35. Images of injured demonstrators raise international profile of the protests.
21 November: President Yanukovych's cabinet abandons an agreement on closer trade ties with EU, instead seeks closer co-operation with Russia. Ukrainian MPs also reject a bill to allow Yulia Tymoshenko to leave the country. Small protests start and comparisons with Orange Revolution begin.
February: Viktor Yanukovych declared winner in presidential election, judged free and fair by observers. His main rival, Prime Minister Yulia Tymoshenko, is arrested for abuse of powers and eventually jailed in October 2011.
December: Opposition candidate Viktor Yushchenko tops poll in election re-run. Rival candidate Viktor Yanukovych challenges result but resigns as prime minister.
November: Orange Revolution begins after reports of widespread vote-rigging in presidential election nominally won by pro-Russian candidate Viktor Yanukovych. Opposition candidate Viktor Yushchenko leads mass street protests and civil disobedience. Supreme Court annuls result of poll.
August: Ukrainian parliament declares independence from USSR following attempted coup in Moscow. In nationwide referendum in December, 90% vote for independence.