Three leading members of the United Front for Democracy against Dictatorship were arrested by the military on Monday morning at Mahachai market in Muang district of Samut Sakhon province and taken to an undisclosed military camp in Ratchaburi province.
Initial reports said only Jatuporn Prompan and Nattawut Saikuar were arrested while talking to the media at Mahachai market about their plan to proceed to Rajabhakti Park in Hua Hin district of Prachuap Khiri Khan province, despite being warned not to go there by the military.
It was later reported that Yossawaris Chuklom, alias Jeng Dokchick, was also arrested at the market by soldiers from the Ratchaburi-based 16th Army Circle shortly after 10am.
The three UDD leaders were taken away in a convoy of two vans of the 16th Army Circle and two white saloon cars.
About 11.30am, the convoy arrived at the entrance of the 16th Army Circle headquarters, where a crowd of reporters were waiting. The convoy zipped past the entrance and on to an unknown destination.
It was believed the convoy was heading to one of the five military camps in the province: Phanurangsi, Srisuriyawong, Burachat and Sanpawut camps in Muang district, and Thap Phaya Lue camp in Suan Phueng district.
Contacted by reporters on the telephone, Maj Gen Chawalit Pongpithak, commander of the 16th Army Circle, said only that the three UDD leaders were at a safe place which would not be disclosed for security reasons.
It was believed they would undergo a session to "fine-tune their attitudes".
Tida Thavornseth, former chair of the United Front for Democracy against Dictatorship, warned the National Council for Peace and Order (NCPO) to be aware the world is watching to see what happens to the three UDD leaders.
In a post on her Facebook page, Ms Tida said it was not known where Mr Jatuporn and Mr Nattawut had been taken, or what their fate would be. She did not seem aware that Mr Yossawaris was also arrested.
"I would like the government and the NCPO to realise that there are problems still to come. How could their trip to pay homage to the past great kings at Rajabhakti Park, as other ordinary citizens have done, be wrong in the eyes of the world and the Thai people?" she wrote.
The two key UDD leaders had not arranged a rendezvous with anyone for any political activity against the NCPO.
"They were performing the duty of good citizens, to check on possible corruption - which is also an objective of this government and all holders of moral standards," Ms Tida went on.
"Should anything untoward happen to Khun Jatuporn and Khun Nattawut, the NCPO will be bombarded with questions from people in society," she said.
Earlier on Monday, Deputy Prime Minister Prawit Wongsuwon, when asked about the UDD leaders' plan to go to Rajabhakti Park, said they should not do so.
"A committee of the Defence Ministry is investigating" the alleged corruption in the construction of the park, he said. "It would be a political issue if they go there. As I have said, soldiers are not playing politics. Whatever is right is right, wrong is wrong," he said.
Asked whether the UDD leaders would be barred from entering the park, he said: "I can only say that they should not go. Let them think for themselves. They are all grownups."
Asked about the calls for the resignation from cabinet of Deputy Defence Minister Udomdej Sitabutr, who as then-army chief was responsible for the Rajabhakti Park project, Gen Prawit said Gen Udomdej would have to make his own decision on that.
"He, as a former army chief, is a man of high maturity. He may already be thinking. I don't need to tell him what he should think about. We are no longer children," Gen Prawit said.
He declined to comment whether the controversy would end with Gen Udomdej's resignation. He said only that the Rajabhakti issue was not the government's weak point.
"We have set up a committee to investigate," he said, referring to the new panel chaired by Gen Chanchai Changmongkol, a deputy permanent secretary for justice.
NCPO spokesman Winthai Suvaree said later the three UDD men had been arrested because they were involved in a political activity, which was not allowed.
The remarks Mr Jatuporn and Mr Nattawut had made in public could be seen as an attempt to incite unrest, and the authorities decided to arrest them, Col Winthai said.
Based on incomplete information, they had criticised the Rajabhakti Park project in strong terms, using the word "corruption", he said.
"What they said was based on their feelings. The government is already acting within its scope of responsibility to clear up the controversy for the public," he added.
Col Winthai said Mr Jatuporn's and Mr Nattawut's actions were not helpful to the ongoing investigation process. They were not officials and had no authority.
It was reported at about 8pm that Mr Jatuporn and Mr Nattawut were released from the Surasi army camp in Kanchanaburi province after signing an agreement outlining their future conduct.
