Almost 100 companies of police and military forces will be deployed to handle protesters who have vowed to shut down Bangkok from Monday.
The protesters plan to set up rally sites at the government office complex on Chaeng Watthana Road, the Victory Monument, Lumpini Park, Ratchaprasong intersection, Asok, Pathumwan intersection and Lat Phrao.
Centre for Administration of Peace and Order (Capo) spokesman Piya Uthayo said yesterday 56 police and 40 military companies will deal with the demonstration on Monday.
There are about 150 personnel in each company.
Mobile traffic units will also be arranged to handle traffic in the inner areas of Bangkok, he said.
Pol Maj Gen Piya said the forces will also be deployed to protect the houses of key figures, including caretaker Prime Minister Yingluck Shinawatra and cabinet ministers.
Pol Maj Gen Piya said Capo had prepared specific work plans to deal with the protest, including relieving traffic congestion, providing security in vulnerable areas, setting up checkpoints and devising security measures in case riots break out.
Meanwhile, PDRC guards detained an armed plainclothes police officer near the Ratchadamnoen Avenue rally site at 11.30pm on Tuesday.
Pol Sgt Thapat Pet-arwut, a squad leader of the Public Affairs Division of the Royal Thai Police Office, was stopped as he was entering the rally site at the Khok Wua intersection, Metropolitan Police Bureau deputy chief Adul Narongsak said yesterday.
The officer was sent to Samran Rat station for questioning.
He was carrying a 9mm handgun, 10 rounds of ammunition and a pack of crystal methamphetamine, Pol Maj Gen Adul said.
Police pressed charges of possessing a Type-1 drug and carrying a weapon, he added.
Public Affairs Division commander Anucha Romyanan confirmed the arrested officer was not assigned to be on duty at the rally site.
He had a record of misconduct and had previously received a warning from his superiors, Pol Maj Gen Anucha said.
Police will set up a panel to consider disciplinary action against Pol Sgt Thapat, who could face dismissal, he said.
Pol Maj Gen Adul called on protesters not to take part in the rally on Monday, saying third parties may be out to incite violence.