Photo taken on Sept. 6, 2019 shows a media briefing held by the Hong Kong police in south China's Hong Kong. The Hong Kong police said Friday that a total of 18 people have been arrested for unlawful assemblies and violent acts at the Hong Kong International Airport on Aug. 13 and Sept. 1. (Xinhua/Mao Siqian)

Li Kam-piu, acting senior superintendent of Traffic New Territories South of the Hong Kong police, speaks during a media briefing in south China's Hong Kong, Sept. 6, 2019. The Hong Kong police said Friday that a total of 18 people have been arrested for unlawful assemblies and violent acts at the Hong Kong International Airport on Aug. 13 and Sept. 1. (Xinhua/Mao Siqian)

The Hong Kong police said Friday that a total of 18 people have been arrested for unlawful assemblies and violent acts at the Hong Kong International Airport on Aug. 13 and Sept. 1.

Lau Wing-kei, deputy district commander of Airport District of the Hong Kong police, said at a media briefing that 12 people have been arrested related to the violent incidents at the airport on Aug. 13.

The offenses of them, aged between 17 and 35, include unlawful assemblies, false imprisonment, participating in riots, disorder in public places, assaulting police, wounding, possession of offensive weapons and others.

The airport was paralyzed two days in a row as protesters flooded into the passenger terminal to stage a sit-in protest on Aug. 13, Lau said, adding that the protest quickly turned confrontational and violent as protesters unlawfully blocked passengers from boarding flights and harshly attacked some innocent visitors.

In relation to the incidents at the airport on Sept. 1, six people, aged between 20 and 26, have been arrested over offenses such as possession of instrument fit for unlawful purposes and intentionally endangering the safety of passengers by throwing objects upon railways.

Pointing out that "the disruptive acts have extended to different transport hubs including the Hong Kong International Airport," Lau said the police are aware that some of the online comments are promoting another protest at the airport on Saturday by obstructing traffic to and around the airport.

Photo taken on Sept. 6, 2019 shows a media briefing held by the Hong Kong police in south China's Hong Kong. The Hong Kong police said Friday that a total of 18 people have been arrested for unlawful assemblies and violent acts at the Hong Kong International Airport on Aug. 13 and Sept. 1. (Xinhua/Mao Siqian)

The airport authority has obtained an injunction order from the court to restrain people from unlawfully and willfully obstructing or interfering with the proper use of the airport.

Lau reiterated that anyone in breach of the order is liable to the offense of contempt of court, and the police will fully support and provide all necessary assistance to the airport authority in enforcing the injunction order as well as access control measures at the airport.

Besides the injunction, the airport authority started access control measures for the terminal buildings at the airport on Aug. 14. Only passengers with a valid air ticket or boarding pass for a flight in the next 24 hours and a valid travel document, or airport staff with relevant identification document will be allowed to enter the terminal buildings.

Lau said the police noticed that some netizens talked about making fake tickets to pretend as passengers to enter the terminal, and warned that this may constitute the offense of using a false instrument, with a maximum penalty of 14-year imprisonment.

Lau stressed that the injunction order also covers the roads connecting to the airport, and if drivers intentionally drive slowly to obstruct traffic, they may be liable to careless driving and dangerous driving under the road traffic ordinance.

"The airport is an essential infrastructure catering to travelers from all around the world," he said, "The police will closely monitor the situation and make respective deployment tomorrow."