Police and protesters clashed in the streets of Brussels on Sunday in demonstrations over government-imposed Covid-19 restrictions, with police firing water cannon and tear gas at demonstrators throwing rocks and smoke bombs, witnesses said.
About 35,000 people took part in demonstrations, police said, which began peacefully before violence broke out.
Protesters wearing black hoods threw stones at police as they advanced with water cannon at the main junction in front of the European Union Commission headquarters, Reuters journalists said.
Facing up to the police lines, the protesters held hands and chanted "freedom". One protester was carrying a placard reading "when tyranny becomes law, rebellion becomes duty".
Protesters also threw smoke bombs and fireworks, the newspaper Le Soir reported. The situation calmed down later, police said.
Belgium tightened its coronavirus restrictions on Wednesday, mandating wider use of masks and enforcing work from home, as cases rose in the country's fourth Covid-19 wave.
There have been 1,581,500 infections and 26,568 coronavirus-related deaths reported in the country of 11.7 million people since the pandemic began. Infections are increasing again, with 13,826 new cases reported on average each day.
Violence has also broken out in anti-restriction protests in Belgium's neighbour the Netherlands in recent days. On Friday, police in Rotterdam opened fire on a crowd.