Ukraine: Chronology of a Crisis

Ukraine is heading toward further political uncertainty after its president, Viktor Yushchenko, dissolved parliament, setting the stage for fresh elections next month. Here are the key events since the so-called orange revolution that brought Mr Yushchenko to power.

November 22 2004: Supporters of Mr Yushchenko - dressed in orange - hold mass protests over what they claim are rigged results showing the prime minister Viktor Yanukovych in the lead in a poll to decide who would succeed President Leonid Kuchma.

December 3: The supreme court rules the vote invalid and orders a rerun of the second round.

December 28: Mr Yushchenko wins the election with 51.99% the vote. The supreme court rejects complaints by Mr Yanukovich of poll violations, and he resigns as prime minister.

Jan 23 2005: Mr Yushchenko is sworn in as president. He picks Yulia Tymoshenko as his prime minister.

September 8: Mr Yushchenko sacks Ms Tymoshenko and her government following resignations of two top officials. Yuri Yekhanurov, a loyal presidential ally, becomes prime minister.

January 10 2006: Parliament votes to sack the government over a gas deal with Russia that sharply raises the cost of imports.

March 26: Mr Yanukovitch's Regions party, more sympathetic to Moscow, comes first in parliamentary elections with 186 of 450 seats, but is outnumbered by the combined "orange" score of 243. Ms Tymoshenko's bloc has the highest number of "orange" seats.

July 18: A new ruling coalition, made up of the president's adversaries, proposes Mr Yanukovich as premier after parliament, all but shut down since March, resumes.

August 3: Mr Yanukovich is set to be approved as prime minister after signing a pledge not to reverse pro-western policies.

December 1: Parliament sacks the foreign and interior ministers, backers of pro-western policies such as joining Nato.

January 12, 2007: Mr Yushchenko's rivals pass a law to reduce his control over government. It comes into effect despite two vetoes by Mr Yushchenko.

February 22: Parliament rejects Mr Yushchenko's nominee as foreign minister. He proposes a compromise candidate, the former economy minister Arseniy Yatsenyuk, who is approved on March 21.

March 13: The opposition storms out of parliament to demand Ukraine return to a pro-western course.

April 2: Mr Yushchenko signs a decree dissolving the chamber and ordering a new election.