Tens of thousands of demonstrators massed under falling snow for a third day in the Ukrainian capital yesterday to support liberal opposition leader Viktor Yushchenko, who says he was cheated of victory in Sunday's poll.
Almost-complete official results show Moscow-backed Prime Minister Viktor Yanukovich the winner in a poll that Western observers say was marked by mass fraud.
A central electoral commission official told reporters the final result would be announced at 4pm, which is almost certain to add to the mounting tension.
The US and the EU have both urged Ukraine not to certify the election result until claims of fraud are investigated. EU foreign policy chief Javier Solana said Ukraine was at a crossroads over the results and protests could turn violent.
But Ukrainian Defense Minister Oleksander Kuzmuk said there would be no movement of troops because of the unrest.
"Despite all the rumors and provocative statements, I want to assure you that there have been no unplanned movements of troops or military equipment. And there will be no such movements in future," he said in a statement.
However, the interior ministry, which is responsible for internal order and has a variety of special forces units at its command, remained silent.
The crisis also threatens to damage economic growth in Ukraine, a potentially wealthy country whose poor management has meant it has been outstripped by its neighbors.
"Not a single responsible economist or politician can pretend there is nothing going on and pretend that everything will be okay if the political situation is deteriorating," Ukraine Finance Minister Mykola Azarov told a news conference.
"Despite a certain reserve of economic stability, this reserve and financial stability could be quickly exhausted if events which we are watching continue."
Protesters, who have brought central Kiev to a halt in support of Yushchenko, confronted riot police by the president's offices on Tuesday night after a day of high drama which saw their candidate proclaim himself president by symbolically taking the oath of office in parliament.
Several thousand Yushchenko supporters, wrapped up against sub-zero temperatures, ringed the building again yesterday.