Anti-government protesters are planning more demonstrations for Sunday in Bangkok and some other provinces.
Pol Col Kissana Phathanacharoen, deputy spokesman for the Royal Thai Police, said on Friday that a so-called "car park" gathering planned for Sunday in Bangkok and other provinces is not only against the law, but also the emergency decree and the Disease Control Act.
As usual, Pol Col Kissana said, the police will gather evidence of illegal activities during any protest and will use it as evidence in court.
Shooting point: Protesters climb onto a structure during a rally near Victory Monument. Some of them were armed with sling-shots to fire objects at police who pushed them back with tear gas and rubber bullets. (Photo: Pattarapong Chatpattarasill)
Red-shirt United Front for Democracy against Dictatorship (UDD) leader Nattawut Saikuar on Friday warned young protesters via Facebook that violent confrontations with authorities could end up as a win for those in power.
Mr Nattawut's message follows a series of street rallies in Bangkok organised by students and their allies that ended with violence, including Friday.
Mr Nattawut is expected to lead a car parade starting at 3pm on Sunday, calling on Prime Minister Prayut Chan-o-cha to step down.
That has prompted Seksakol Atthawong, assistant minister at the Prime Minister's Office, to vow to seek legal action against Mr Nattawut for alleged sedition. Mr Seksakol is also petitioning the Anti-Money Laundering Office to look into sources of funds being used to finance the anti-government rallies.
Mr Nattawut pledged that the vehicle rallies would be peaceful and would end with motorists tooting car horns from the start to the end of the national anthem at 6pm.
"I think you don't want to see the armed forces coming out," Mr Nattawut said to his followers. "As for those in power, I am not so sure. You'd better watch your game carefully."
Protesters took to the streets in cars and motorcycles in Bangkok on Aug 1, 2021, demanding Prime Minister Prayut Chan-o-cha resign over his handling of the Covid-19 crisis. Similar rallies were held in other provinces. (Video: Jetjaras Na Ranong)
Rallies culminating in violence could be playing into the hands of those in power, he warned.
The Metropolitan Police Bureau (MPB) said it has been pursuing legal action in 300 cases against suspects over violence at past rallies.
Pol Maj Gen Piya Tawichai, deputy commissioner and spokesman for the MPB, said that 199 of those cases were now fully investigated.
The MPB on Wednesday called for soldiers to help quell clashes but an armed forces source said troops may be used only to protect key locations, leaving police to handle demonstrations.