HONG KONG -- Hong Kong's riot police officers entered the city's airport Tuesday evening and clashed with protesters after hundreds of flights were canceled for a second consecutive day, with the sit-ins paralyzing one of the world's busiest air transport hubs.
A video posted on Twitter shows a tense exchange in which an officer takes down a civilian, only to be swarmed by protesters, including a mask-wearing man who grabs the officer's club and starts to beat him with it. Cornered and fearing danger, the officer appears to draw a handgun and points it at the crowd, which then disperses.
The airport suspended check-ins of passengers late Tuesday afternoon as thousands of anti-government protesters swarmed the departure and arrival halls of the main terminal building. Monday's closing marked the first time that Hong Kong International Airport had been shut over the actions of people.
U.S. President Donald Trump expressed hope that the situation will be resolved for all sides with no casualties.
"The Hong Kong thing is a very tough situation -- very tough," Trump told reporters during a visit to Morristown, New Jersey.
"It's a very tricky situation," he said. "I think it will work out and I hope it works out, for liberty. I hope it works out for everybody, including China. I hope it works out peacefully. I hope nobody gets hurt. I hope nobody gets killed."
Cathay Pacific Airways, the city's flagship carrier, alone canceled more than 200 flights on Tuesday, as it urged passengers to "postpone nonessential travel from Hong Kong" for the next two days.
Protesters began returning to the airport by early afternoon. Video footage showed hundreds of people -- mostly clad in black -- gathered in the departure hall, with some holding posters and sitting on the floor. Like Monday's sit-in, Tuesday's assembly was not approved by police.
The Hong Kong police said their department was "closely monitoring" the sit-in at the airport. "We will consider to use force if necessary," said one spokesperson, without elaboration, at a news conference.
Swire Pacific, Cathay's parent company, issued a statement around the same time the airport suspended check-ins, saying it fully supported the carrier's move to implement Chinese government "directives to ensure safety and its zero tolerance approach to illegal activities."
"We resolutely support the Hong Kong SAR government, the chief executive and the police in their efforts to restore law and order," the company said. "We condemn all illegal activities and violent behavior... We must act now to stop the violence and preserve the stability, peace and prosperity of Hong Kong."
Cathay had come under heavy criticism in Chinese media and social media in recent days, with some calling for a boycott of the airline for insufficiently backing Beijing's official stance on the Hong Kong protests.
Also on Tuesday, medical workers staged sit-ins at 13 hospitals around Hong Kong during the lunch hour to protest against what they say has been excessive police force against protesters.
Some of the demonstrators placed a bandage over one eye to draw attention to an incident in which police allegedly shot a young female protester in the eye with a beanbag bullet during a demonstration in the bustling commercial district of Tsim Sha Tsui on Sunday.
Meanwhile, the Civil Human Rights Front, which has organized several mass protests since June that have drawn up to an estimated 2 million people to the streets, on Tuesday said it is organizing another march on Aug. 18.
The rally will call for ending what they say is the excessive use of police violence against demonstrators, in addition to their five demands: the complete withdrawal of a now-suspended extradition bill; rescinding the characterization of protesters as rioters; the unconditional release of arrested protesters; the formation of an independent commission to investigate the police; and the implementation of universal suffrage.
Violence intensified across Hong Kong on Sunday, as police fired tear gas inside a rail station and shot a protester from a short range and demonstrators hurled petrol bombs at officers. The escalation prompted a spokesperson at the Hong Kong and Macau Affairs Office of the State Council to warn of "signs of terrorism" at a news conference on Monday.
On Tuesday, Hong Kong Chief Executive Carrie Lam, the city's top official, assembled her cabinet to deal with the city's biggest political crisis since the handover to China from Britain in 1997, saying that the city had entered an "emergency situation."
At a news conference, Lam said the latest round of noncooperative demonstrations and violent attacks by protesters have seriously affected the daily lives of ordinary people. She reiterated that the violence must stop to restore public order and repair the economy, warning that Hong Kong was being pushed down a "deep abyss."
To cushion the disruptions caused by the protests at the airport, the Civil Aviation Administration of China on Tuesday said it will increase the capacity of nearby mainland airports.
This week's developments helped push shares of rival airports higher on Tuesday. Shenzhen-listed Shenzhen Airport surged 10%, its daily trading limit, while Shanghai-listed Guangzhou Baiyun International Airport jumped more than 4%.
Nikkei staff writer Coco Liu contributed to this article.