BANGKOK -- Thailand's Prime Minister Prayuth Chan-ocha says he has assigned the Royal Thai Army to investigate after Facebook Inc. removed 185 accounts and groups allegedly engaged in an information-influencing operation in Thailand run by the military.

That followed Facebook's announcement a day earlier that it had deleted 77 accounts, 72 pages, 18 groups and 18 Instagram accounts for violating its policy against government interference, which is defined as co-ordinated inauthentic behaviour on behalf of a government entity.

"Facebook took action like this. It can be interpreted in many ways. We must make it clear," said Prayuth.

About 703,000 accounts followed one or more of these pages, about 100,000 accounts joined at least one of these groups and around 2,500 people followed one or more of the Instagram accounts. Facebook said.

Facebook says the network of accounts originated in Thailand and targeted domestic audiences in its southern provinces, where the army faces a longstanding insurgency movement. The people behind the network used both authentic and fake accounts, posting their content on multiple pages to make it look more popular than it was. The majority of page postings appear to have occurred in 2020.

The Facebook report says the network posted primarily in Thai about news and current events, including content in support of the Thai military and the monarchy. The posts included calls for non-violence, regional Covid-19 updates, allegations of violence by the insurgent groups in southern Thailand and criticism of separatist and independence movements.

"Although the people behind it attempted to conceal their identities and co-ordination, our investigation found links to the Thai military's Internal Security Operations Command," Facebook said.

On Thursday, three activists including Yingcheep Atchanont, Sarinee Achavanuntakul and Winyu John Wongsurawat, filed a suit with the Administrative Court in Bangkok seeking an order to stop the Royal Thai Army's information operation. The three said they have been targeted in such operations.

They said they also planned to contact Facebook and the United Nations' Special Rapporteur on Freedom of Expression seeking an investigation into army's information operations against Thai civilians.

"The army has no authority to commit such information operations," Yingcheep told reporters. "The government should protect people who want to express their opinions, not create propaganda and attack those who have differing views."

The issue of army information operations has surfaced during parliamentary debates.

Nattacha Boonchaiinsawat, a lawmaker from the opposition Move Forward Party, accused the army of misusing funds to foment hatred toward critics of the government. The army responded by saying it just trains officers for public relations, to promote a positive image for the military.

In October 2020, Twitter disclosed it had uncovered a network of 926 accounts allegedly involved in information operations linked to the army. It said the accounts were engaging in amplifying pro-Royal Thai Army and pro-government content and also targeting prominent political opposition figures.

Apart from in Thailand, Facebook said last month that it had detected and removed attempts to reestablish a presence on the platform by military-linked networks in Myanmar, where the army took over in a Feb. 1 coup. Facebook had removed those accounts.