Prague's Old Town Square turned into a battlefield as police intervened to disperse a rally of football and hockey team fans protesting the ban on sporting events as part of anti-Covid measures.
Stones and firecrackers were thrown by the protesters, while the police used tear gas and water cannons.
According to some witnesses there are wounded.
The authorities decided to dissolve the demonstration because the participants - about 2,000 - far exceeded the allowed number of 500 for the rallies.
Most of the participants in the demonstration wore no masks.
The protest also concerned government policies in general against the pandemic.
"People are protesting because the government fell asleep during the summer and did not bring solutions to the crisis. It had to shut down and it failed. The responsibility is theirs," one of the participants who arrived specifically from Ostrava (north) told the site seznam.cz. , city seat of the Banik football club.
A similar demonstration took place yesterday also in Bratislava.
In the Slovak capital, a few hundred fans but also members of far-right groups gathered in front of the government headquarters to reject the measures against the coronavirus epidemic.
Here, too, the police had had to resort to the use of tear gas and water cannons against the participants with stones and bottles calling for the resignation of Prime Minister Igor Matovic.