Thai police used tear gas, water cannon and rubber bullets on Sunday as they tried to stop protesters from marching on the office of Prime Minister Prayuth Chan-ocha calling for him to resign.
More than 1,000 protesters took part in the demonstration, which police had so far not dispersed.
Many demonstrators carried mock body-bags to represent coronavirus deaths, as they blame the prime minister and his government for mismanaging the Covid-19 pandemic.