MINSK — Tens of thousands of Belarusian opposition supporters gathered for the largest protest rally in recent history in Minsk as President Alexander Lukashenko rejected calls to step down in a defiant speech.

Crowds of protesters marched through the streets to the central Independence Square on Sunday, with an AFP journalist estimating the turnout at more than 100,0000, a scale of protest not seen since the breakup of the Soviet Union.

Belarusian independent news site Tut.by called the rally "the largest in the history of independent Belarus".

Columns of demonstrators raised victory signs and held flowers and balloons as a sea of protesters gathered in Independence Square, the focus of peaceful demonstrations in recent days.

"Now we're changing history," said 26-year-old Yekaterina Gorbina, a content manager.

Popular opposition candidate Svetlana Tikhanovskaya had called for a weekend of protests after leaving for neighbouring Lithuania following the disputed election, which gave Lukashenko 80 per cent of the vote.

Other major towns and cities in the ex-Soviet country of nine million also saw large rallies, local media reported.

More and more Belarusians have taken to the streets over the last week to condemn Lukashenko's disputed victory and a subsequent violent crackdown by riot police and abuse of detainees.

Unusually, tightly controlled state television news aired a short item on the "alternative protest" in Minsk, while not showing anti-Lukashenko slogans.

Outside Belarus, hundreds of Czechs and Belarusians, some holding the traditional red and white Belarusian flag and portraits of Tikhanovskaya, gathered in Prague's historic centre Sunday in support of the protests.

There were also smaller shows of support in Romania and Poland, AFP journalists said.

Lukashenko, who has ruled Belarus for 26 years, is facing an unprecedented challenge to his leadership.

The 65-year-old strongman held a rare campaign-style rally on Independence Square before the opposition protest.

He told flag-waving supporters: "I called you here not to defend me... but for the first time in a quarter-century, to defend your country and its independence."

State television said 65,000 people attended the rally, though an AFP reporter put the number closer to 10,000.

"The elections were valid," Lukashenko said in a sometimes emotional speech.

"We won't give away the country!" he vowed. — AFP