Sources said that despite heavy police presence, tens of thousands of people poured into Independence Square on Sunday, many carrying opposition's red and white flags, and chanted "freedom" and anti-government slogans, the BBC reported.

After gathering in the square, some demonstrators moved towards the "Hero City" war memorial and the presidential palace, however they were blocked by a security cordon forcing them to disperse.

State television released a video showing Lukashenko arriving at the presidential palace by helicopter, wearing a flak jacket and carrying an automatic weapon.

The protesters have accused Lukashenko of literally stealing the election, which was conducted without any observers and want him to resign.

The president has blamed foreign powers of instigating the protests and has vowed to crush the unrest.

Government forces have carried out a violent crackdown on the protesters which has seen the death of at least four people, with the demonstrators also claiming to being tortured by the security forces in prison.

According to official results, Lukashenko - who has ruled Belarus for 26 years - won more than 80% of the vote in the August 9 election and opposition leader Svetlana Tikhanovskaya 10%.

There were no independent observers and the opposition alleges massive vote rigging.

Tikhanovskaya, who was forced to flee to neighbouring Lithuania the day after the election, vowed to "stand till the end" in the protests.