Ukrainian opposition leaders last night promised indefinite demonstrations in response to the presidential election victory of Prime Minister Viktor Yanukovich, condemned as fraudulent by America and election monitors.
With counting almost over from Sunday's election, officials have announced an unbeatable lead for Mr Yanukovich, the government candidate, over his main challenger, Mr Viktor Yushchenko.
The result flies in the face of exit polls that put Mr Yushchenko in the lead, and it has triggered nation-wide protests.
Abroad, condemnation of the election came from the United States and European Union officials. President George Bush's envoy, US Senator Richard Lugar, led international protests, declaring: "It is now apparent that there was a concerted and forceful programme of election day fraud and abuse enacted with the leadership or co-operation of authorities."
Dutch Foreign Minister Bernard Bot, holder of the rotating presidency of the European Union, said the bloc's 25 member-states will summon their Ukrainian ambassadors to voice concern.
But Russian President Vladimir Putin, who has given high profile support to Mr Yanukovich, issued a statement congratulating him, saying "the battle had been hard-fought, but open and honest, and his victory was convincing".
In the capital, Kiev, tens of thousands of opposition protesters, wearing trademark orange ribbons, took to the streets to denounce the result.
Mr Yushchenko yesterday made a televised appeal for hundreds of thousands of supporters to converge on Kiev "on carts, cars, planes". Meanwhile, police and army units were deployed around government installations in the capital, with the authorities promising harsh measures against disorder.
A joint statement from the interior ministry, secret police and prosecutor general, said: "We are prepared to put an end quickly and firmly to any lawlessness."
Conditions in Kiev were calm, with hundreds of stewards with orange arm bands marshalling demonstrators and keeping them away from police units guarding government buildings.
Four opposition cities, including Kiev and the western stronghold of Lviv, declared Mr Yushchenko as the rightful president, with more than 20 local councils following suit.
With almost all ballots counted, election officials gave Mr Yanukovich 49 per cent of the vote, and Mr Yushchenko 46 per cent, contradicting a string of exit polls that gave victory to the challenger.
A day of high drama began with Mr Bruce George, mission chief of the Organisation for Security and Co-operation in Europe, condemning a repeat of violations he first found in the previous round of voting last month. "I have to say the authorities did not respond positively to our appeal. The second round did not meet a considerable number of requirements."
The 600 international monitors said the election was one of the most fraudulent Europe has seen in recent years. A long litany of violations have been reported, including the filling-in by election officials of thousands of extra absentee ballots and the manipulation of election lists. The pattern appears to show concerted action by election officials to deny votes in the opposition strongholds of the north and west, while adding extra votes in the government heartlands of the east.
Most bizarrely, Mr George reported the use of invisible ink to disqualify opposition votes and the pouring of acid by thugs into ballot boxes in opposition areas.
In the pro-government east, monitors questioned official turnout figures of 98 per cent. Growing disobedience raises the question of whether Mr Yanukovich can in fact govern, with large parts of the Ukraine refusing to recognise his authority.