Human rights group Viasna-96 says at least 106 people taken into police custody mainly in Minsk.
Alexander Lukashenko, the embattled Belarusian president who has ruled the country for 27 years, has said his position wields too much power as he promised a referendum on constitutional reforms next year.
Lukashenko spoke on Thursday at a special assembly to debate political reform, an event his opponents dismissed as a sham exercise amid months-long anti-government demonstrations which have rocked the country since a contested election last year.
But while he appeared to critique the constitution, Lukashenko dismissed mass protests against his rule as a foreign-directed “rebellion”.
The 66-year-old did not elaborate, but over the past several months he has repeatedly accused the West of fomenting the demonstrations.
“We must stand up to them no matter what, and this year will be decisive,” he told the 2,700 participants of the All-Belarusian People’s Assembly in a televised speech.
Appearing in front of the slogan “Belarus: a test of endurance”, Lukashenko also claimed the “mutiny” against him had been ended.
“The blitzkrieg failed. We saved our country. For now,” he said.
Main opposition candidate Svetlana Tikhanovskaya and her supporters say the August 9 election result was rigged.
Some poll workers have also alleged the vote, which handed Lukashenko a landslide victory, was manipulated.
The opposition had urged Belarusians to take to the streets to protest against Thursday’s gathering. Local media footage showed police vans waiting outside in case of unrest.
‘Clinging on to power’
Lukashenko convened the assembly to discuss plans for the country’s development.
Politicians close to the authorities had hinted, prior to the meeting, at the possibility of an amnesty for political prisoners.
“We must closely consider issues of social development … think about the possibility of adjusting the basic law,” Lukashenko told delegates, without specifying when the proposed changes would be revealed.
Most of the delegates attending the two-day meeting are pro-government local deputies and officials who were elected at closed sessions.
“Lukashenko is gathering loyalists at the so-called All Belarusian People’s Assembly to legitimise (the) usurper in the eyes of the people,” said Franak Viacorka, an adviser to Tikhanovskaya, who is now exiled and living in Lithuania.
“Because Lukashenko understands that he lost people’s support, and he is still clinging on to power by all possible means,” Viacorka said.
During his rule, Lukashenko has stifled dissent and relied on support, as well as cheap energy and other subsidies, from his main ally, Russia. Moscow sees the former Soviet republic as a buffer state against NATO.
On Thursday, he thanked Moscow for its support in the face of protests, but reaffirmed that the union agreement between the two countries should not limit Belarus’s independence.
“The assistance of the Russian Federation was of the utmost importance for us,” Lukashenko said. “As long as we and Russia stand back to back, no one will bring us to our knees.”
The mass protests that have gripped Belarus, an ex-Soviet nation of 9.5 million people, have been met with a harsh response from authorities.
Police have used stun grenades, tear gas and truncheons to disperse the largely peaceful rallies, the largest of which attracted up to 200,000 people.
Human rights groups allege that more than 30,000 people have been arrested since the protests began, and that thousands of them were brutally beaten.
The United States and the European Union have responded to the accusations of vote manipulations and the crackdown by introducing sanctions against Belarusian officials.
Lukashenko on Thursday accused the West of harbouring aggressive intentions, but at the same time urged it to restore political ties and economic cooperation.