Belarusian police carried out arrests of protesters attending a banned demonstration in the capital, Minsk, on Saturday amid a rising wave of discontent challenging the country's authoritarian government.

About 700 protesters braved the threat of a crackdown after police earlier raided the offices of a human rights organization and arrested an opposition leader.

While it remains unclear exactly how many protesters were detained, the human rights group Viasna said more than 400 people had been arrested.

Among those arrested were about 20 journalists, according to the Belarusian Journalists' Association.

The nongovernmental organization (NGO), said authorities raided its office ahead of the protest and arrested 57 people, including foreign observers. The group has recorded more than 100 arrests of opposition supporters in the days leading up to Saturday's protests.

Police on Saturday also detained leading opposition leader Vladimir Nekliayev as he was on a train to Minsk.

President Lukashenko in power for 23 years

Belarus has witnessed rare protests drawing thousands of people in recent weeks against a new tax for those who work less than six months a year. Facing pressure, the government then suspended collection of the tax.

The protests have channeled broader discontent against a mismanaged state-run economy under President Alexander Lukashenko, who has ruled the country for 23 years.

Lukashenko initially allowed the protests but this week warned Western intelligence agencies were supporting a "fifth column" of provocateurs to overthrow him. State television tried to back up the claim by reporting the discovery of alleged weapons caches.

Like his close ally Russian President Vladimir Putin, Lukashenko has long warned of a "color revolution" such as those in Ukraine and Georgia toppling his government.

cw/jm (AFP, AP, dpa)