The military is going after prominent red shirts by issuing summons, raids, detention and the closure of some border crossings in the wake of Thursday's power seizure.
In Tak's Mae Sot district, dozens of gun-toting soldiers yesterday stormed into the house of Meena Paksae, or Chartchai Kua-angkulkachorn, to detain him for questioning.
Chartchai had earlier led a group of red shirts to a hospital and removed a pro-political reform banner.
Known to spearhead efforts to set up a red-shirt radio station in Tak, he has close ties with a red-shirt hardliner Wutthipong Kochthammakhun, known as "Go Tee".
Soldiers found a handgun in Chartchai's house.
Border-crossing points in Ubon Ratchathani and Nong Khai are now closed to most people. Thais are allowed to travel into Thailand while foreigners are allowed to leave.
No Thai citizen is allowed to leave Thailand via these border crossings and no foreigners are allowed to enter through them.
"Soldiers will be deployed at all piers along the Mekong River, too. We will also conduct patrols," a senior military officer added.
Sources said the military had practically closed the border crossings in a bid to prevent people summoned by the National Peace and Order Maintaining Council (NPOMC) from leaving the country.
According to the sources, Pichet Tabudda, a red-shirt leader and a red DJ, sneaked into Laos just before the power seizure. He was sighted at a famous cafe in Laos.
Pichet led some 30 red shirts to rally in front of a military base in Ubon Ratchathani on Wednesday.
The Suranaee Command yesterday announced that the Sai Taku border-trade checkpoint in Buri Ram would be closed indefinitely out of concern that some ill-intentioned people may try to smuggle weapons into Thailand to trigger violence.
The border-trade checkpoint in Mae Hong Son has been closed, too.
"We will reopen it when the situation returns to normal," said Colonel Amnaj Srimark, the chief of a military taskforce.
The NPOMC, led by Army chief General Prayuth Chan-ocha, sprung into action on Thursday and announced a mission to quickly restore normalcy to Thailand.
The country had been struggling with political turmoil and violence for more than six months prior to the military intervention.
In Sa Kaew, soldiers yesterday strictly searched vehicles and people going in and out of the Aranyaprathet border crossing.
The military raided facilities where several red radio stations were based and seized equipment.