Twenty-six protesters were detained for breaches of the emergency decree and other laws on Monday, when Thalufah and Thalugaz groups rallied at different spots in Bangkok, Metropolitan Police spokesman Pol Maj Gen Piya Tawichai said on Tuesday.
The Thalufah members began to converge at Nang Lerng intersection at 4pm, he said.
They threw bags of coloured paint and water bottles, scattered leaflets and stretched cloth banners with anti-government messages over police barricades and razor wire.
At 5pm, the protesters cut the wire and tried to remove the barricades in front of Phra Nakhon Technology College.
Pol Maj Gen Piya said they were warned their actions were against the law and told to leave. The protesters ignored the warning and continued to fire objects including glass marbles and ball bearings from catapults. They also hurled flares and fireworks at the police, he said.
He said police moved in to dislodge the protesters about 5.30pm and dispersed them by around 6.30pm.
Twenty-six protesters were detained and six of them were found to have been arrested and released on bail after earlier protests.
Police would oppose court bail for the repeat offenders, Pol Maj Gen Piya said.
He said the Thalugaz group gathered and protested on Mitmaitree road from 8.40pm-9.40pm. They threw fireworks, fired projectiles from slingshots and lit flares in a provocative manner before leaving on motorcycles.
According to Pol Maj Gen Piya, since July there have 234 protest-related incidents involving 869 suspects, of whom 624 had already been arrested and faced legal action .