Anti-government protests in the capital could intensify in response to what the protesters have described as heavy-handed police tactics to contain them, according to the Metropolitan Police Bureau (MPB).
Clashes between protesters and police are likely to grow in intensity and more violent, said deputy commissioner Pol Maj Gen Piya Tawichai, citing the bureau's intelligence sources.
The police have stumbled on spikes strewn allegedly by the protesters on roads around Din Daeng intersection where they have engaged in daily clashes with police.
Pol Maj Gen Piya said the spikes were a danger to motorists and the police. He added that government properties may be torched during future rallies.
The predominantly young protesters on motorcycles, who call themselves members of the Thalu Gas group, announced a break from protests yesterday and it remains unclear when they will resume.
Pol Maj Gen Piya said the latest clash on Monday afternoon saw the protesters hurling objects, such as marbles, firecrackers, petrol and ping-pong bombs, at police stationed around the intersection.
They also threw ping-pong bombs and firecrackers as they moved towards police who had formed a security perimeter in the area.
A handful of police were injured and several government properties were damaged in the process, Pol Maj Gen Piya said.
At least three protesters were arrested by police, who also seized 29 firecrackers, 30 marbles, a quantity of dried cannabis and several motorcycles.
The suspects face charges that include illegal assembly of more than five people in maximum strict and controlled zones to cause a commotion in the capital, failure to comply with authorities' orders and possession of Type 5 narcotics without permission.
Since last month, 287 protesters have been arrested and are facing prosecution on protest-related charges.
Investigators so far have issued 127 court-approved warrants to summon 16 leaders and 111 rally participants for questioning, Pol Maj Gen Piya added.
Investigators have also summoned the parents of at least 20 young protesters to come in for questioning.