As darkness fell at Bangkok's Democracy Monument, the numbers of student-led protesters calling on the government led by Gen Prayut Chan-o-cha to quit swelled well past 10,000.
The peaceful but high-spirited rally began on Sunday afternoon and by evening engulfed an area stretching from the Democracy Monument roundabout, where activists and comedians spoke from a stage, to beyond Khok Wua intersection in the direction of Sanam Luang.
The Metropolitan Police Bureau put the crowd at 12,000 at around 7pm, while organisers claimed more than 20,000 were calling for a restoration of full democracy.
Vehicles were barred from entering the area for the safety of the demonstrators, while police were using the compound of Satriwithaya School as a command centre for officers to maintain law and order.
Prime Minister Prayut Chan-o-cha has pleaded for calm and patience from security authorities deployed at the rally site, while a small group of pro-royalist agitators withdrew from the area to avoid confrontation.
Speakers at the rally held by the student-led Free People group reaffirmed their three demands: the dissolution of the House, the commencement of writing a new constitution and an end to harrassment of government critics.
The organisers will read out a statement near the end of the protest repeating the three demands. They will also reiterate their opposition to a coup or the formation of a "national unity" government to end the political impasse.
They said their protests have expanded beyond students to include a wide cross-section of the population. "Free People is now not limited only to students, but also includes people from different aspects of society, ranging from artists and labourers to people from all walks of life," it said.
Trakul Meechai, a political scientist at Chulalongkorn University, told Thai PBS the government and Parliament should hold an urgent meeting to address their calls and make clear their positions on the demands.
The new round of anti-government protests started on July 18 before spreading into several provinces, particularly at school and university campuses.