Several thousand protesters opposed to Thailand's military-backed government have clashed with police in the capital, Bangkok.
Protesters say police used tear gas and batons to disperse them
The crowd staged a rally outside the house of Prem Tinsulanonda, a senior adviser to Thailand's king.
The protesters say Mr Prem was behind a bloodless coup which removed former Prime Minister Thaksin Shinawatra.
Rocks and bottles of water were thrown at police, in the most violent demonstration since the 2006 coup.
Protesters, mostly supporters of the ousted Mr Thaksin, have been holding nightly rallies in Bangkok since early June.
Clashes broke out after they marched to demonstrate outside Mr Prem's house on Sunday evening and anti-riot police tried to disperse them.
Several people, including police officers, were taken to hospital with minor injuries.
Bangkok police officials said they would issue arrest warrants for the protest leaders on Monday.