Hong_Kong_Protests_56017
A man looks at the flight information board shows outbound flights was cancel at the Hong Kong International airport. Image Credit: AP

Hong Kong airport authorities canceled remaining flights on Monday after protesters swarmed the main terminal building for a fourth day, the biggest disruption yet to the city's economy since demonstrations began in early June.

Thousands of black-clad protesters on Monday packed the arrival area, where they had gathered for a three-day sit-in that was originally planned to end last night. The protests, initially sparked by opposition to a bill that would allow extraditions to mainland China, have become increasingly violent in recent weeks, with demonstrators targeting public transportation in a bid to pressure the government.

It was unclear how many flights were impacted, according to Doris Lai, a spokesperson for the Hong Kong Airport Authority. The airport said in an earlier statement that it was aiming to restore operations as soon as possible after canceling all flights for the rest of the day, except those already in the air.

Shares of Cathay Pacific Airways Ltd., Hong Kong's main airline, tumbled to a 10-year low after the news. The government planned a press briefing for 5:15 p.m. local time. The Stoxx Europe 600 Index came off its session high and contracts for all three main U.S. equity indexes erased earlier gains.

China stepped up its rhetoric on Monday, saying protesters have committed serious crimes and showed signs of "terrorism." Hong Kong has come to a "critical juncture" and all people who care about its future should say no to violence, Yang Guang, a spokesman for its Hong Kong and Macau Affairs Office, told reporters on Monday as protesters gathered at the airport.

"All those who care about Hong Kong's future should come out and stand against all criminal acts and perpetrators of violence," Yang told reporters.

Tang Ping-keung, deputy commissioner of police, said it was too early to say whether force would be used to clear the airport. "It will be up to commander to decide" whether to use tear gas, he told reporters.

Police responded with tear gas and rubber bullets at various locations - including inside a metro station for the first time. Dramatic videos showed riot police firing weapons at close range and beating some protesters, many of whom wore yellow hard hats and gas masks. Some 13 protesters were injured, including two in serious condition, RTHK reported, citing hospital authorities.

Cathay Pacific has come under fire after some of its employees joined the demonstrations. A Chinese state-run company told employees not to fly Cathay Pacific on business or personal trips, according to people familiar with the matter.

Hong Kong leader Carrie Lam has refused to yield to a series of demands, including that she withdraw the bill and step down from her position. Authorities in Beijing remain supportive of her government, which has warned of an economic crisis if the demonstrations drag on.

Read an Explainer on Hong Kong's Protest Movement

The protesters are resorting to flash mobs and violence as their numbers diminish, according to Steve Vickers, chief executive officer of risk consultancy Steve Vickers and Associates and a former head of the Royal Hong Kong Police Criminal Intelligence Bureau.

China in recent weeks has toughened its stance toward the movement and doubled down on its support for the police. The Hong Kong and Macau Affairs Office, its top agency overseeing the former British colony's affairs, has held unprecedented briefings condemning violent protesters and called on the people of Hong Kong to oppose them. An overseas edition of the Communist Party mouthpiece People's Daily said last month that police should take stern action to restore order.

Hong Kong called former deputy police commissioner Lau Yip-shing out of retirement last week to handle major upcoming public events including celebrations marking the 70th anniversary of the founding of the People's Republic of China in October. Lau had overseen the government's crackdown on protesters during the 2014 pro-democracy Occupy movement.

Authorities had denied permits over the weekend for protests in all but Victoria Park, but demonstrators took to the streets anyway. Police made more arrests on Sunday after detaining 16 people on Saturday, with local media reporting that officers may be dressing as protesters and infiltrating their ranks to help with detentions.