VIDEO - Thousands have gathered in the Thai capital for Saturday's protests
Thousands of people have protested in the Thai capital Bangkok calling for reform of the political system, including the role of the monarchy.
It was one of the biggest protests in years with at least 15,000 people, police said. "Down with feudalism, long live the people," chanted some.
There were no reports of violence.
Since July, rallies have called for the resignation of Prime Minister Prayuth Chan-ocha who took power in a 2014 coup and won disputed elections last year.
Saturday's student-led demonstration moved from the campus of Thammasat University to a park next to a grand palace used for royal ceremonies.
Demonstrators say they plan to stay overnight and march to the offices of the prime minister on Sunday morning.
"I hope the people in power will see the importance of the people," student leader Panupong "Mike" Jadnok, told the crowd, according to Reuters news agency. "We're fighting to put the monarchy in the right place, not to abolish it."
The calls for royal reform are particularly sensitive in Thailand, with criticism of the monarchy punishable by long prison sentences.
Organisers gave a much higher estimate for Saturday's turnout, saying 50,000 people had attended. A protest in August drew around 10,000 protesters.