Demonstrators are demanding Prime Minister Prayuth Chan-ocha, who took power in a military coup in 2014, speeds up reforms. The protest movement, which erupted almost a month ago, is gathering momentum.
An anti-government protest in Thailand's capital Bangkok drew at least 10,000 people on Sunday, police said, making it the largest political demonstration the kingdom has seen in years.
The student-led protests began nearly a month ago and have been held on an almost daily basis ever since.
Demonstrators are demanding a revised constitution, an end to the harassment of government critics and reforms to the monarchy.
The last demand is particularly sensitive in Thailand — anyone criticizing the monarchy faces between 1.5 to 15 years in jail.
They also want Prime Minister Prayuth Chan-ocha, who took power in a 2014 military coup, to resign.
'Down with the dictatorship'
Crowds of demonstrators shouting "down with the dictatorship" gathered around the capital's symbolic Democracy Monument. Others held dove-shaped cutouts representing peace.
Student activist Parit Chiwarak made an appearance at the rally, despite being granted bail on Saturday after being arrested for his pro-democracy work.
Flanked by supporters, he held a sign that read: "10-point Monarchy Reform" – referring to a list of demands setting out changes that student protesters want to see implemented.
Police were also present, as well as a much smaller group of royalists who support the monarchy.
Waves of protests
Thailand has experienced multiple coups ever since the army toppled the absolute monarchy in 1932, replacing it with a constitutional monarchy.
The government held elections last year but these were seen as rigged, sparking public anger.
The latest wave of protests began in February this year after a court ordered the pro-democracy Future Forward Party to disband. The onset of the coronavirus pandemic, however, put a pause on these protests until recently.
kmm/mm (AP, AFP, dpa)