Politicians listen to an announcement that the Tymoshenko and Yushchenko coalition has collapsed during a parliament session in Kiev on September 16 2008 [EPA]

The collapse of Ukraine's ruling coalition follows years of political infighting within the former Soviet republic, which finds itself split between those who want to strengthening ties with Russia and those who favour further integration with Europe.

January 2005: Viktor Yushchenko becomes president following the Orange Revolution. His appointment follows days of popular protests in the capital Kiev against the rigging of a presidential election in favour of the pro-Russian candidate Viktor Yanukovych.

September 2005: Yushchenko sacks Yulia Tymoshenko, the prime minister and his Orange Revolution ally, after she accuses his close allies of corruption. Yushchenko supporters say the accusations are part of a push for power by Tymoshenko.

March 2006: Ukraine holds parliamentary elections following changes to the constitution that increase the powers of the president. Yanukovych's Regions Party gains the most seats and he eventually becomes prime minister in July.

April 2007: Yushchenko orders parliament dissolved, accusing Yanukovych of trying to undermine his authority. The political scene is deadlocked for months, with supporters of the rival parties facing off in the streets of Kiev.

September 2007: Parliamentary elections are held in which the Regions Party and the president's Our Ukraine party suffer heavy losses, while Tymoshenko's party makes major gains. Tymoshenko again becomes prime minister.

August 2008: Andriy Kyslynsky, a leading ally of Yushchenko, accuses Tymoshenko of "high treason and political corruption" for not siding with Georgia in its conflict with Russia. Tymoshenko refutes the accusation.

September 2008: Yushchenko accuses Tymoshenko of planning a "coup" against him after her supporters side with the pro-Russian opposition to limit the president's powers. Yushchenko pulls out of a coalition with Tymoshenko.

September 16, 2008: The speaker of Ukraine's parliament announces that the coalition has officially collapsed. Parliament has 30 days to try to form a new ruling coalition. If negotiations fail, Yushchenko can dissolve parliament and call snap elections.

Source: Agencies