The Ukrainian parliament has voted to sack the government less than four months since the last government was sacked by the president. The BBC News website looks at the reasons for the latest crisis, and asks what happens next.
Why did the parliament sack the government?
A range of political forces united to vote the government down, and each may have had a different reason.
The vote came in the wake of widespread criticism of the government for signing a controversial deal on gas supplies from Russia last week.
However, it may have had more to do with the forthcoming Ukrainian parliamentary election, due on 26 March.
Who will now run the country?
Actually, the existing government of Prime Minister Yuri Yekhanurov will stay in power until the parliamentary election. Both President Viktor Yushchenko and his opponents agree on this.
They disagree on whether it will be an acting, caretaker government, or a fully legitimate government in the normal sense of the word.
After the election, the new government will be formed from forces that group together to create a parliamentary majority.
What was the point of sacking the government, but ordering it to stay in office?
One opposition member of parliament said that the move "deprived the cabinet of the opportunity to make decisions".
Another explanation is that it further batters Mr Yushchenko's political image and dents his authority, in the run-up to the March election.
The parties that voted to sack the government also publicly disassociated themselves from the gas deal with Russia.
Does the parliament have the power to sack the government?
Constitutional reforms, which were meant to have come into force on 1 January, were supposed to have given the parliament this power.
However, Mr Yushchenko has said he will challenge the legitimacy of the vote in the Constitutional Court.
He has not made clear on what grounds this challenge will be made.
Will the Constitutional Court rule on the question soon?
It seems unlikely. The court is short of judges, because the parliament has been blocking Mr Yushchenko's appointments.
Which were the main political forces behind the vote to sack the government?
They range from the left to the right of the spectrum, including the Communist Party, the Social Democratic Party of Ukraine (United), the Party of the Regions, the People's Bloc of Volodymyr Lytvyn, and the Yulia Tymoshenko Bloc.
The leaders of at least three of these parties - Viktor Yanukovych, Yulia Tymoshenko and Volodymyr Lytvyn - are in with a chance to become prime minister after the election.
Will the vote cause the Ukraine-Russia gas deal to be scrapped?
Most analyst see no immediate danger to the deal.
Mr Yekhanurov has said he will do all he can to protect it.
Why is the gas deal under attack?
Some politicians say the higher price of gas will damage Ukrainian industry, and that ordinary consumers will also be asked to pay more than they can afford before long.
Others attack the part of the deal which says that Ukraine will buy all its gas - Russian and Central Asian - through an intermediary that is half-owned by the Russian gas monopoly, Gazprom. Their view is that this arrangement will encourage corruption, and leave Ukraine too dependent on Russia.
What does Russia make of this latest crisis?
Few Russian political forces gave much support to the Orange Revolution, and some now appear to be taking delight in Mr Yushchenko's embarrassment.
If his first year in office had been a resounding success, it might have encouraged an outbreak of people power in Russia itself.
From this perspective, Russia might also welcome the prospect of Mr Yushchenko sharing power with a hostile parliament and prime minister - especially if that prime minister is Viktor Yanukovych, whom Russian President Vladimir Putin openly backed during the 2004 election.
On the other hand, the possibility that the next prime minister will tear up the gas deal - and the threat of new disruption to Russian gas exports - would presumably be unwelcome in Moscow.