He said the charges might include defamation, criminal offences and violations of other people's rights.

Chidchai did not specify whether the targets would include key figures in the People's Alliance for Democracy, which has organised the demonstrations.

"The authorities have been collecting evidence. The police don't need to take action now while the climate is heated and are dealing with the protests in a restrained manner. But they have gathered evidence, which will be used when the time is right," Chidchai said.

"This is not a threat: it's my appeal. The public should not be affected or have their rights violated," he said.

Chidchai said there were complaints from monks in three Buddhist temples near the protest site - Makut Kasatriyaram, Somanas Worawihan, and Benjamabophit - about "noise

pollution" from the loudspeakers at the rally. He said he had instructed police to look into the matter.