BANGKOK (AFP) - Thai police detained three university students at Bangkok cinemas on Thursday while at least two theatres in the junta-ruled nation cancelled opening screenings of The Hunger Games.

A female student was escorted out of a cinema in a high-end mall in the capital after flashing the three-finger salute from the films - an unofficial symbol of resistance against the army's May coup - while police detained two other students, who did not appear to be protesting, outside a nearby cinema.

"Two students are under interrogation at the police station," Colonel Kittikorn Boonsom of Bangkok Metropolitan Police told AFP.

"The third detainee is a female student nabbed in front of Siam Paragon's cinema because she flashed an anti-government sign several times," he said.

The army wants to hold "talks" with the female student, said Kittikorn, adding: "She may be taken to the army camp for attitude adjustment."

The detentions come after five other students were briefly held by the military Wednesday for flashing the three-finger sign during a speech by Thai Premier Prayuth Chan-ocha in the northeastern province of Khon Kaen.

Earlier on Thursday around 20 police officers, surrounded by dozens of journalists, gathered outside the Scala cinema in downtown Bangkok where the theatre had cancelled showings of the latest Hunger Games film.

There were a few students milling around but no protests, according to an AFP reporter at the scene.

Ratthapol Supasopon, one of the two detained male students who said he was part of a Facebook group giving away free tickets for the film, was taken away by police after speaking to journalists.

"It is just an activity to watch a movie... We will not show the three fingers," said the Thammasat University student.

"Everyone is afraid to do or to say something wrong... Today, in Thailand, we don't have freedom anymore," he said before being driven away.

The other male student detained at the cinema was seen carrying a copy of George Orwell's anti-authoritarian novel Nineteen Eighty-Four.

Kittikorn confirmed it was the same man who had been arrested five months earlier after reading the novel while eating a sandwich.

Political assemblies of more than five people were banned by the army two days before it ousted the kingdom's government on May 22, with students turning to small but creative methods of protest to show their opposition.

The five students held briefly in the northeast Wednesday were asked to return Thursday with their parents to sign undertakings not to engage in any political activity.

Sasinan Thamnithinan, a human rights lawyer, said only two agreed to sign but all five had been released.

"Two of them have signed to accept army conditions to stop activities after pressure but the other three refused to accept government authority," she said.

Showings of The Hunger Games have been cancelled in at least two Bangkok cinemas run by the APEX group.