Approximately 2,000 women took part in the latest protests to demand an end to President Alexander Lukashenko’s rule.
Tens of thousands of opposition supporters marched in the Belarusian capital of Minsk on Sunday despite authorities deploying a heavy police presence.
The protest came a day after officers detained hundreds of demonstrators at a women’s march in the capital.
Military trucks and vehicles have rolled into the centre of Minsk as anonymous hackers leaked what they said was the personal data of more than 1,000 police officers in retaliation for a crackdown on anti-government demonstrations.
The protest movement calling for the departure of longtime President Alexander Lukashenko has been holding mass rallies every week since his disputed election win on August 9.
The latest opposition protests began at 11:00 GMT on Sunday with the opposition calling on social media for demonstrators to gather in central Minsk as well as in other cities.
People holding red-and-white protest flags gathered at the “March of Justice” that occupied the whole of a central avenue and walked towards the heavily guarded Palace of Independence, where Lukashenko has his offices.
They held placards with slogans such as “Cowards beat up women” and “Get out!”.
Riot police in black balaclavas sporadically detained protesters carrying flags and signs at the start, while some people took shelter in a shopping mall and in a fast-food restaurant to escape arrest.
Belarusian opposition news sites posted video and photos of the military convoy driving into central Minsk and bringing rolls of barbed wire with it.
The protest comes after riot police cracked down on peaceful female demonstrators on Saturday who had come out wearing shiny accessories for a so-called “Sparkly March”. Police dragged protesters into vans, lifting some women off their feet and carried them.
Belarusian interior ministry spokeswoman Olga Chemodanova said on Sunday police detained 415 people in Minsk, and 15 in other cities, for breaking rules on mass demonstrations. She said 385 had been released.
Chemodanova warned Belarusians they could face criminal charges for organising such protests.
The number of detentions on Saturday was far higher than at a similar protest last week, prompting the opposition’s Coordination Council to warn of a “new phase in the escalation of violence against peaceful protesters”.
Among those held was one of the most prominent faces of the protest movement, 73-year-old activist Nina Baginskaya, although she was later released.
The aggressive police tactics prompted an opposition Telegram channel – Nexta, which has more than two million subscribers – to publish what it said was a list of the names and ranks of more than 1,000 police.
“As the arrests continue, we will continue to publish data on a massive scale,” said a statement on the messaging app on Saturday evening. “No one will remain anonymous even under a balaclava.”
Protesters have sought to expose the identity of police officers who appear at demonstrations in plain-clothes or in uniforms without insignia or name badges, trying to pull off their masks and balaclavas.
The government said it would find and punish those behind the data leak.
“The forces, means and technologies at the disposal of the internal affairs bodies make it possible to identify and prosecute the overwhelming majority of those guilty of leaking personal data on the Internet,” said Chemodanova.
In power since 1994, Lukashenko was officially declared the winner of last month’s polls with 80.1 percent of the vote. The opposition, however, alleges fraud and considers opposition leader Svetlana Tikhanovskaya, who has taken shelter in Lithuania, to be the real winner.
In a video clip, Tikhanovskaya urged her fellow Belarusians to continue fighting for a country in which it is worth living in the so-called “March of Justice”.
“Every week you show yourself and the world that the Belarusian people are a force,” the 38-year-old said.
Tikhanovskaya is set to meet European Union foreign ministers in Brussels on Monday as the EU prepares sanctions against those it blames for rigging the election and the violent crackdown on protesters.
Authorities have jailed many of Tikhanovskaya’s allies who formed the leadership of the Coordination Council, or driven them out of the country.
One of her campaign partners, Maria Kolesnikova, has been imprisoned and charged with undermining national security.
Lukashenko has dismissed opposition calls for his resignation and sought help from Russia’s President Vladimir Putin, who has promised law enforcement backup if needed and a $1.5bn loan.