Police used tear gas, water cannon and rubber-coated bullets to disperse protesters trying to march on Thai Prime Minister Prayuth Chan-ocha’s office to demand he resign over his handling of the coronavirus pandemic and its economic effect.
Some protesters attacked police and eight police officers and at least one reporter was injured during the clashes on Sunday, police said.
Police did not say if any protesters were injured but said 13 protesters were arrested.
Protest organisers called for the demonstration to end just after 6pm (11:00 GMT) but a standoff between the police and hundreds of protesters continued for several more hours before the police dispersed the crowd just before the start of a 9pm (14:00 GMT) curfew that is in force in the Thai capital.
More than 1,000 people joined the demonstration.
Police intervened with force after some protesters tried to dismantle barbed wire and metal barricades set up by the authorities to block roads from Democracy Monument to Government House where the prime minister works.
Deputy police spokesman Kissana Phathanacharoen said the protesters attacked police with “ping-pong bombs, slingshots and firecrackers”.
Street protests against the prime minister have been held in recent weeks by several groups, including Prayuth’s former political allies, as frustrations grow over the mounting coronavirus infections and the damage the pandemic has done to the economy.
Thailand reported 11,397 infections and 101 deaths on Sunday, bringing the cumulative total to 403,386 cases and 3,341 fatalities, the vast majority from an outbreak since early April that is being driven by the highly transmissible Alpha and Delta COVID-19 variants.
The protest marked one year since the first of a wave of large-scale street protests led by youth groups that attracted hundreds of thousands of people across the country.
The momentum of those protests stalled after authorities began cracking down on rallies and detaining protest leaders, and after new waves of COVID-19 infections broke out.