Updated at 8:50 p.m. BJT 

Seven labor unions in the aviation industry of Hong Kong issued a statement on Sunday, strongly condemning the protesters' act of blocking the airport.

A group of radical protesters paralyzed the Hong Kong International Airport on Sunday and obstructed the normal operation of this critical infrastructure. The protester's behavior is "extremely selfish" and damaged the livelihood of airport staffers, read the statement.

The unions urged the Airport Authority Hong Kong to enforce the law strictly, exercise its power in accordance with the law to protect the public interest of Hong Kong residents.

Updated at 6:30 p.m. BJT 

According to the police, violent protesters vandalized the Tung Chung Station, destroying the gate entries, breaking the glass in the customer service center and damaging firefighting equipment since roughly 5:30 p.m.

Some radical protesters burned a Chinese national flag and set fire to barriers in Tung Chung, seriously blocking the traffic. The police warned the protesters to "leave immediately."

In a statement from MTR, longer waiting times in the Tung Chung Line platforms can be expected.

Updated at 6:00 p.m. BJT 

Hong kong Station issued an emergency announcement, asking people to leave the station immediately.

Updated at  5:40 p.m. BJT 

The Mass Transit Railway (MTR) said in a statement that the train service has been disrupted on the Airport Express due to trespassing and foreign objects were found on the track near the Airport Station.

"For safety reasons, train service has been adjusted because a number of facilities were damaged at various stations," MTR said.

A large group of protesters hurled numerous iron poles, bricks and rocks on the railway near the Airport Station after 4:00 p.m., with some even breaking on to the track, according to the police.

The protesters are participating in an unauthorized assembly, police said, adding that since an injunction order is in force at the airport, the protesters may be liable to "contempt of court."

Updated at 3:35 p.m. BJT 

Since 1:00 p.m. local time, a group of protesters started gathering around bus stops at the Terminal of Hong Kong International Airport, the police said.

At around 2:00 p.m., protesters charged at barriers, pointed laser beams at the Airport Authority workers, and blocked roads with trolleys and mills barriers.

The police issued a warning, urging all protesters to stop their illegal acts and leave immediately.

Updated at 3:05 p.m. BJT 

Sections of the Airport Express in Hong Kong were suspended on Sunday, according to the Mass Transit Railway (MTR) operator.

A notice at subway stations said the suspension was requested by the Hong Kong SAR government and the Airport Authority.

Hong Kong Station, from where the Airport Express starts, has been closed, according to CGTN reporter He Weiwei at the scene.