Tensions mount in Kiev's streets

By Helen Fawkes
BBC News, Kiev

There are fears the demonstrations may turn violent

There were angry scenes as Prime Minister Viktor Yanukovych was officially declared the elected president of Ukraine.

Opposition MPs shouted: "Lies, lies".

Then the celebrations started for pro-Yanukovych politicians.

Earlier, opposition MPs demanded that the central election commission delay the announcement while there was an investigation into claims of mass violations on polling day.

Rival candidate Viktor Yushchenko had said he was willing to take part in a re-run of the vote, if it was honest.

But allies of the prime minister say he won the ballot fairly.

Thousands of pro-Yanukovych supporters poured into the capital on Wednesday.

"I'm for Yanukovych, 100%." "Yanukovych, Ukraine is with you," they chanted.

Mounting tension

With hundreds of thousands of protesters from both sides on the streets of Kiev by evening, tension was mounting.

The peaceful and sometimes carnival atmosphere at Independence Square had been replaced with an air of tension.

There are fears there may be violent confrontations.

Following the official election result, a number of people started to leave the main square and head in the direction of the presidential administration.

They will join the opposition supporters who marched on the presidential building on Tuesday night.

The opposition leader has accused the authorities of planning to crush the protest with violence.

But the outgoing president, Leonid Kuchma, has denied they will use force to end the largest demonstration in Ukraine's history since independence.