Police will not allow students or activists to stage political activities to mark the 83rd anniversary of the 1932 Siam Revolution Wednesday, national police chief Somyot Poompunmuang said.
"Police will take decisive action against anyone who flouts the NCPO's order," he said Tuesday, referring to a National Council for Peace and Order ban on political gatherings of more than five people.
He was responding to reports that several student groups and activists plan to stage symbolic gestures on Wednesday.
Eight university students charged with breaking the NCPO order by staging an anti-coup gathering outside the Bangkok Art and Cultural Centre on May 22 are reportedly planning to gather and report to Pathumwan police station.
The move is being considered by observers as a symbolic protest to defy the NCPO order.
Meanwhile, seven university students in Khon Kaen, known as the Dao Din group, are also expected to report to police Wednesday after failing to make a scheduled appearance on June 19.
They were arrested on May 22, the first anniversary of the military coup, during a protest at the Democracy Monument in Khon Kaen.
Police want them to report tomorrow instead to avoid any symbolic gestures.
Meanwhile, the Cross-Cultural Foundation has urged police against seeking arrest warrants against the Dao Din students for failing to report on Friday.
They also called for an end to civilian trials in military courts, echoing calls made recently at a UN Human Rights Council meeting in Geneva.
Viboon Boonpattaraksa, 59, father of Dao Din leader Jatupat, defended the students' actions.
"Previously, they had been able to discuss the problems in local communities, then one day after the coup took place their mouths were shut, hence their reaction," he said about the students' behaviour.
"I'm a lawyer myself and have been observing their activities all along. I don't think they have done anything really wrong. It depends on how you would judge them," said Mr Viboon from Chaiyaphum province.
He said the Dao Din students had no colour-coded leanings.
"They acted as their conscience dictated," said the father, adding that all he can do is lend moral support to his son.
Meanwhile, Lt Gen Suchart Pongput, commander of the Army's Signal Department, said Tuesday that authorities plan to invite only local journalists to a gathering next week to discuss their style of reporting, not foreign media as earlier reports stated.
"We will urge them to ask government people 'constructive questions' and not distort facts in their reports," he said.
The National Broadcasting and Telecommunication Commission will issue the invitation to the journalists, Lt Gen Suchart added.