Understanding the geography of Ukraine !
What caused the protests?
- The trigger was the government's decision not to sign a major partnership deal with the EU, despite years of negotiations aimed at integrating Ukraine with the 28-nation bloc. That decision was announced on 21 November.
- Thousands of pro-EU Ukrainians poured onto the streets of the capital, urging President Yanukovych to cancel his U-turn and go ahead with the EU deal after all. He refused, and the protests continued.
- On 30 November in the early hours riot police waded in heavily to break up a student protest, leaving dozens of people injured.
- Anger at the TV pictures only fuelled anger with President Yanukovych, and boosted the crowds in Independence Square.
- The authorities sought to defuse the anger through measures such as the suspension of the mayor of Kiev and release of detainees.
- On 17 December, Russia and Ukraine announced a major deal under which Russia would buy $15bn-worth (£9.2bn; 10.9bn euros) of Ukrainian government bonds and slash the price of Russian gas sold to Ukraine.
- The deal - of critical importance to Ukraine at the time when the country is struggling to avoid default - appeared to take the wind out of the sails of the protest movement, with the number of demonstrators dwindling.
- But when a pro-opposition journalist, Tetyana Chornovol, was beaten up by unknown assailants on Christmas Day there was an outcry.
- The approval of tough new laws to curb street protests then appeared to further fuel the anger in Kiev.
Who are the protesters?
- The protesters are mainly from the Kiev area and western Ukraine, where there is a greater affinity with the EU, rather than in the Russian-speaking east and south - though they include eastern Ukrainians too.
- Parliament's three opposition movements have all been involved in the protests. Vitali Klitschko, the former world heavyweight boxing champion and leader of the Udar (Punch) movement, has been a prominent demonstrator. He is very pro-EU and plans to run for president in 2015.
- One of the most important Ukrainian protesters is Arseniy Yatsenyuk, parliamentary leader of the country's second biggest party, called Fatherland. He is an ally of former PM Yulia Tymoshenko, a former prime minister now in jail, who is an arch-rival of the president.
- A new development since Ukraine's last major round of unrest, in the 2004 Orange Revolution, is the presence of ultra-nationalists. The far-right group called Svoboda (Freedom) is also protesting, led by Oleh Tyahnybok (pictured second from left).
- Another radical right-wing group, which has been blamed for trying to provoke the police, is Bratstvo (Brotherhood), which is not a parliamentary party. And yet another, Right Sector, was linked to clashes in January.
Why is Yulia Tymoshenko important?
- Internationally, Tymoshenko has become a symbol of opposition to Mr Yanukovych, and a cause celebre in the EU.
- She was jailed in 2011 for criminally exceeding her powers over a gas deal with Russia in 2009, and is serving a seven-year sentence. Many EU politicians accept her allegation that her trial was politically motivated. The European Court of Human Rights did not go as far but did rule that her pre-trial detention had been "arbitrary and unlawful".
- Critics of Tymoshenko argue the abuse of office conviction was just the tip of the iceberg. They allege that she lined her pockets as prime minister while betraying the Orange Revolution in which she played a key role.
- The EU set her release as a key condition for signing the association agreement with Ukraine - but Mr Yanukovych resisted the pressure to free her. Tymoshenko says she has a serious back ailment and wants to get treatment in Germany.
How has the West reacted?
- The EU's official position is that the door remains open for Ukraine to sign the association agreement but it has put any new negotiations on hold until there is a clear commitment to sign.
- EU foreign ministers have sought to reassure Russia that the deal would not undermine Moscow's interests.
- Washington has said it is considering all options, including sanctions, towards Ukraine's leaders after the crackdown on 30 November.
- US Secretary of State John Kerry expressed "disgust" at the decision by the authorities to "meet the peaceful protest... with riot police, bulldozers, and batons".
- Both the EU and US have condemned the tough new anti-protest laws, saying they are incompatible with Ukrainians' democratic aspirations.
Is Russia pulling the strings in Kiev?
- To many observers, the deal struck between Russia and Ukraine on 17 December points to a carrot-and-stick approach by the Kremlin.
- Mr Yanukovych's abrupt snub to the EU came after Russia exerted strong economic pressure on Ukraine.
- The 2004 Orange Revolution led to Mr Yanukovych's removal from power after his election was judged to have been fraudulent. Russia backed him then - and backs him now.
- In the run-up to the EU decision, Russia imposed time-consuming border checks and a ban on Ukrainian sweets - and threatened other measures.
- Apart from Ukraine's heavy reliance on Russian gas, many Ukrainian firms - especially in the country's Russian-speaking east - depend on sales to Russia.
- Mr Yanukovych, who was democratically elected in 2010, still has a strong support base in eastern and southern Ukraine, and there have been street demonstrations by his supporters.
- For centuries Ukraine was controlled by Moscow and many Russians see Ukraine as vital to Russian interests.