Ukraine's Central Election Commission has declared Prime Minister Viktor Yanukovych the winner of Sunday's disputed presidential election.

Authorities say the prime minister won more than 49 percent of the vote - nearly three percentage points ahead of opposition challenger Viktor Yushchenko.

The announcement Wednesday came as tens of thousands of protesters continued to mass in the capital, Kiev, alleging widespread fraud in the vote. Crowds packed the Ukrainian capital's main square, waving flags and chanting Mr. Yushchenko's name. Some have slept in tents, despite the cold and snow.

Protesters marched to the Election Commission following the announcement.

The European Union had warned of consequences in its relations with Ukraine if the results were announced before a review is conducted. European and U.S. monitors allege widespread fraud in the vote.

The White House says it is disturbed about indications of wrongdoing.