BANGKOK —Thailand's army chief lashed out at opposition figures on Friday in an emotional speech in which he portrayed politicians and academics as threats to national security and even the monarchy.

The criticism by Gen. Apirat Kongsompong came less than three months after direct military rule officially ended in Thailand, although the new civilian administration is led by the former army chief who overthrew the previous elected government.

Apirat described collusion between unidentified "communist" politicians and "extreme left" academics who had studied abroad, a veiled jab at members of the opposition Future Forward Party, popular with social media-savvy young people.

He said they were using social media to spread "propaganda" and brainwash and mobilize the youth, likening the situation to Hong Kong protests led by young people.

He did not identify the people he was referring to in the speech, which lasted for more than an hour, but one silhouetted picture he showed was easily recognizable as Future Forward's charismatic leader, Thanathorn Juangroongruangkit.

"Propaganda in Thailand is severe and worrying. There is a group of communists who still have ideas to overthrow the monarchy, to turn Thailand to communism," Apirat told an auditorium of military officers, policemen and uniformed students.

The monarchy is legally above reproach in Thailand, and the new constitutional monarch who was officially crowned in May, King Maha Vajiralongkorn, has taken several steps since the death of his father to increase his authority, including taking direct control of two key army units.

Thanathorn, who has denied the military's accusations that he is anti-monarchy, said Apirat's attempt to link him to the Hong Kong protests was the latest attempt to instigate hatred.

"We started the Future Forward Party with good intentions for the country," he said in a Facebook post.

"We wanted to be a part of the force pushing Thailand towards democracy, creating equality in society and leaving it a better one for the next generations."

Last week, the military filed a sedition case against Thanathorn and others, accusing them of stirring unrest with talk of amending the 2017 constitution written by allies of the military.

It followed a public seminar they held in the Muslim-majority south, in which the first article of the constitution — stating that Thailand is one indivisible kingdom — was discussed.

"They are being shrewd, talking of amending the first article without stating directly what they want, knowing this will affect other articles about the monarchy," Apirat said.

"This article invoked the blood our ancestors had shed to keep this land. I can tell you I will never allow it, even to my dying day," Apirat said.

The army chief cast the military as loyal to the nation and the royal family.

"Don't forget that Thailand is the only country in this region that has never been colonized, thanks to past kings," Apirat said. — Reuters