Belarusian security forces began detaining people on Sunday as tens of thousands of protesters gathered in Minsk for the seventh straight weekend calling on veteran President Alexander Lukashenko to step down.
Riot police pulled people out of crowds and hauled them away into vans, a Reuters witness said. The Russian news agency Interfax said at least 10 people had been detained. Several metro stations were shut and the mobile internet disrupted.
Belarus plunged into turmoil after Lukashenko claimed a landslide victory in the Aug 9 election that his opponents say was blatantly rigged. He denies electoral fraud and says the protests have foreign backing.
Lukashenko was inaugurated for a sixth term on Wednesday in a ceremony held without any prior announcement, sparking more protests and condemnation from the European Union, the United States and Britain.
Russia said the EU's decision not to recognise Lukashenko as the legitimate president contradicted international law and amounted to indirect meddling in the country.
"We are witnessing a power crisis in Belarus with an authoritarian administration that is not able to accept the logic of democracy," French President Emmanuel Macron told le Journal du Dimanche in comments published on Sunday.
"It is clear that Lukashenko must go."
A former Soviet collective farm manager, the 66-year-old Lukashenko has been in power for over a quarter of a century and shows no inclination to resign, buoyed by support from traditional ally Russia.
With Western countries preparing to impose new sanctions on Minsk, Belarusian Foreign Minister Vladimir Makei accused them of attempting to sow "chaos and anarchy".
Police detained 150 people during protests on Saturday, Russia's RIA news agency quoted the interior ministry as saying.