Belarus opposition leader Alexander Kozulin tried to register for a meeting to be adressed by President Lukashenko today. Instead when he entered Minsk's central hall plain-clothes officers knocked him to the ground and took him and some 20 other people away to a police station.
Lukashenko, in power since 1994, stands for re-election on March the 19th. He is ahead in opinion polls.
Kozulin is a former rector of the Belarus state university, and is lying well behind in third place. According to supporters he has been badly beaten. Dozens have gathered outside the police station to protest, and another opposition candidate has called a street rally for tonight. Such gatherings are illegal.
Kozulin was charged with "hooliganism", but has since been released.
The incident comes a day after the Belarus secret service, which retains the Soviet-era KGB acronym, said it had foiled an opposition plot to stage a coup after the election.
The US and EU has warned it will monitor Belarus's election, and will tighten sanctions if it is not free and fair. Lukashenko is accused by many of rigging elections to obtain a supine parliament, and muzzling the press.
Leading opposition candidate Alexander Milinkevich, who has called the street rally, condemned the police action and also denies the opposition is involved in any coup plot.
Despite the criticisms Lukashenko has much popular support, and claims his sticking to Soviet command economics means Belarus has avoided the chaos that has afflicted other former communist states.