Thailand's military government on Wednesday turned up the pressure on its opponents, filing a legal complaint against critics of a proposed new constitution and detaining 10 people in connection with social media postings.

Election Commissioner Somchai Srisuthiyakor filed the first complaint under a new law meant to discourage campaigning against the draft charter, which will be put to a referendum on Aug. 7. The penalty for breaking the law is up to 10 years in prison and a fine of up to 200,000 baht ($5,715). The complaint was based on material on the Facebook page of a social group based in the northeastern province of Khon Kaen, a hotbed of dissident activity.

"We're trying to make an example of those who are explicitly and aggressively posting things about the draft constitution onto the Internet," said Somchai. "People are allowed to post opinions agreeing or disagreeing with the new draft, but we encourage that they do so in an academic fashion with reason and logic, rather than using foul and strong language."

The law prohibits acts of unrest and campaigning with a provocative, aggressive or violent manner to influence voters, but Prime Minister Prayuth Chan-ocha and other officials have made clear they disapprove of any criticism. The government insists its own ambitious plans to publicize the charter's contents are strictly educational. Prayuth seized power in May 2014 after staging a coup against an elected government.

Separately, the military detained 10 people associated with opposition to its rule. Government spokesman Col. Winthai Suvaree said the suspects, including several in Khon Kaen, were detained in connection with social media postings. Thailand's Computer Crime Act has broad definitions that are often applied to expressions of political opinions.

Those arrested were taken for detention at army bases, where they can be held for a week without any charges.

"The capture of these people is not in accordance with either international or national laws," said Poonsuk Poonsukcharoen, a member of the Thai Lawyers for Human Rights group. "The power that the army received from the new legislation to capture and detain people for expressing opinions against the draft constitution is being used in the wrong way. These arrests are creating a sense of fear among the public."

More than a dozen activists were detained Wednesday evening in Bangkok when they staged a non-violent protest against the morning's detentions.