Belarus said Wednesday that protesters could face serious criminal charges after hundreds were arrested at demonstrations over the removal of opposition candidates from the presidential election.

Protesters took to the streets in the capital Minsk and several other cities on Tuesday after election officials refused to allow rivals to President Alexander Lukashenko to stand in the August 9 vote.

Police said they had detained more than 250 people across the country, alleging the protests were sparked by "internet provocateurs".

Many have been charged with administrative violations and face fines or detention for up to 13 days, rights group Viasna said.

But the Investigative Committee, which investigates major crimes, said it was also launching a probe into organising and participating in gross violations of public order, which has a maximum jail term of three years.

Meanwhile the Organization for Security and Cooperation in Europe, which has sent observers to monitor presidential polls in Belarus since 2001, said a mission would not be deployed this year "due to lack of invitation".

Belarus police said they have detained more than 250 people across the country after protests over the banning of several opposition candidates from the presidential election
Belarus police said they have detained more than 250 people across the country after protests over the banning of several opposition candidates from the presidential election AFP / Sergei GAPON

Amnesty International condemned "excessive and unnecessary use of force by police" during the demonstrations.

Riot police forced some protesters to kneel on the floor of police vans and some were hit in the face, Viasna said.

Police in turn accused demonstrators of injuring six riot police.

More than 40 protesters detained in Minsk were released by Wednesday afternoon, Viasna said.

Lukashenko, a former collective farm chief, has been president for 26 years and will seek a sixth term in the August election. He will stand along with four other candidates.

In defiant comments on Wednesday, Lukashenko said he would not accept preaching on democratic values from Western countries.

"They start hinting to us: make sure it's all democratic, that there are no street clashes," he said during a meeting with supporters in a provincial city.

Investigators said they were looking at video footage of the demonstrations
Investigators said they were looking at video footage of the demonstrations AFP / Sergei GAPON

"Don't point the finger at us over how we live," he said, though claiming that he is "not against" international observers at the polls.

"You want to monitor elections, please come tomorrow," he said.

The electoral commission on Tuesday struck out Lukashenko's jailed main rival Viktor Babaryko and another popular opposition figure, Valery Tsepkalo, citing issues including violations in income declarations and lack of signatures from supporters.

Thousands of Babaryko supporters on Wednesday evening were queueing outside the election commission headquarters in Minsk to confirm their signatures, watched over by a strong police presence.

German foreign ministry spokesman Rainer Breul called the decision "a heavy blow against basic democratic principles" which "limits the opportunity" for Belarusians to freely choose their president.

Babaryko was arrested last month over suspected financial crimes and is being held in the KGB security service's prison.

The commission allowed the candidacy of one high-profile opposition figure: Svetlana Tikhanovskaya, the 37-year-old wife of a jailed vlogger who stood for president after her husband was barred.

In a video statement posted on social media, Tikhanovskaya condemned police violence.

"Police, riot police, what are you doing? You are beating up your mothers, sisters, brothers and children," she said.

"People came out for a peaceful protest. People came out to express their discontent."

Her husband, vlogger Sergei Tikhanovsky, had mounted a high-profile campaign urging Belarusians to "stop the cockroach" as he calls the moustachioed strongman.

He is in a police jail and has been charged with organising a gross breach of public order.

The ballot is going ahead despite the country of nine million people confirming more than 65,000 coronavirus cases. Lukashenko has refused to impose a strict lockdown.