Updated: Aug. 13, 2019, 3:06 p.m.
Suzanne Sataline contributed to this report from Hong Kong
Riot police clashed with pro-democracy demonstrators at the Hong Kong's international airport Tuesday evening, with all departing flights cancelled for a second straight day.
The protestors once again took over the facility's main terminal, with periodic skirmishes with helmeted police wielding batons.
Scuffles broke out between police and demonstrators as medics took an injured person out of the terminal. A contingent of riot police used pepper spray to disperse protesters as they tried to block an ambulance taking the man away. Police detained at least two people.
Hong Kong's airport authority said operations had been "seriously disrupted."
The airport protests over the past two days are part of 10 weeks of demonstrations by Hong Kong residents against their perceived erosion of freedom and lack of autonomy under Chinese control of the territory.
China's United Nations mission said the protesters had smashed public facilities, paralyzed the airport, blocked public transport and used lethal weapons, "showing a tendency of resorting to terrorism."
The U.N. High Commissioner for Human Rights Michelle Bachelet urged Hong Kong authorities to exercise restraint and investigate whether their forces fired tear gas at protesters in ways that are banned under international law.
U.S. President Donald Trump, who last week took a hands-off stance on the protests, told reporters the Hong Kong situation "is a very tough situation, very tough. We'll see what happens, but I'm sure it will work out...." He expressed the hope that no one would get hurt and "for liberty."
"I hope it works out for everybody, including China, by the way," Trump said.
In a later remark on Twitter, Trump said, "Our Intelligence has informed us that the Chinese Government is moving troops to the Border with Hong Kong. Everyone should be calm and safe!" State-run media showed videos of security forces gathering across the border in Mainland China.
The protests present the biggest challenge to Chinese rule of the semi-autonomous territory since its 1997 handover from Britain.
The decision by the airport authority to cancel Tuesday's out-bound flights came just minutes after it suspended all passenger check-in services when protesters blocked passengers from entering their departure gates, and advised the general public not to come to the airport.
The airport was already struggling to return to normal after reopening a day after hundreds of flights in and out of the airport were cancelled by a similar sit-in demonstration. Some angry travelers anxious to leave Hong Kong got into heated arguments with protesters as Tuesday's demonstrations escalated, with some managing to push their way through the protest lines.
The unprecedented shutdown of one of the world's busiest airports was an extension of the street protests that have gripped the Chinese territory for more than two months. Dozens of protesters were injured Monday after riot police fired tear gas and non-lethal ammunition after the protesters blocked roads and defied police orders to disperse.
The government counted 54 people injured Monday, including two who were hospitalized in serious condition, and 28 who were listed as stable, according to the Hospital Authority.
The protests began as a quest to stop a bill that would have allowed Hong Kong to send criminal suspects elsewhere, including mainland China. Demonstrators are now demanding the the right to directly vote for their next leader in a free and fair election, and an independent inquiry into alleged police brutality.
Carrie Lam, Hong Kong's embattled leader, defended police during a press conference Tuesday, saying they had to make "on-the-spot decisions" under "extremely difficult circumstances." Lam said she would address the protesters' demands "after the violence has been stopped and the chaotic situation that now we are seeing could subside."