Protesters are stepping up violent and politically motivated activities while enjoying legal protection from some supporters, national police chief Pol Gen Suwat Jangyodsuk said on Thursday.
He was responding to the blazes at a number of traffic police kiosks in Bangkok early Thursday morning following a daily anti-government rally in Din Daeng district on Wednesday evening.
"Violent movements are escalating and spreading... These acts are not the works of normal criminals. Since August, over 400 people have been arrested. As the arrests continue, they learn more about legal technicalities," he said.
"They have a legal team ready to defend them around the clock. When someone is arrested, they'll show up at once. I told interrogators that they should also gather evidence for other criminal offences such as illegal association," Pol Gen Suwat said.
Asked about people behind the movements, the national police chief said they wanted to create unrest and tarnish the image of security forces for political gains.
Police would have to end these violent movements, he said.
Pol Maj Gen Piya Tavichai, deputy commissioner of the Metropolitan Police Bureau, said that about 30 people on 15 motorcycles torched six traffic police booths from 12.30am to 2.40am on Thursday. They included traffic control booths at Saphan Khwai, Pradiphat, Ratchaprasong, Urupong and Mit Samphan intersections.
The burning followed a protest by the Thalu Gas group at Din Daeng intersection from 6.20pm to 11.20pm when demonstrators burned motorcycle tyres, blocked traffic and threw big firecrackers, fireworks and bombs at police.