Hong Kong protests: Police officer mobbed by crowd pulls gun on protesters amid violent clashes at airport

As violence rages in Hong Kong, Donald Trump said he hoped nobody there would get hurt.

He also said the situation worked out for everybody involved, including China.

The US president was speaking to reporters in New Jersey when he was asked about the volatile situation.

"The Hong Kong thing is a very tough situation - very tough," he told reporters.

 "We'll see what happens."

"It's a very tricky situation. 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," the president said.

Donald Trump has said he can't imagine why the US is being blamed for the Hong Kong protests.

Pro-government figures have suggested the US is encouraging the unrest to destabilise the city's government, which has close ties with Beijing.

Donald Trump has said US intelligence agencies believe China is moving troops towards Hong Kong.

"Everyone should be calm and safe!" Mr Trump said.

It is unusual for state leaders to discuss information from intelligence briefings.

Video from Mike Bird, a Wall Street Journal reporter, appears to show protesters in Hong Kong seizing a baton from a police officer and then beating him with it.

Emergency staff have taken an injured mainland Chinese man away from Hong Kong's airport after angry protesters who accused him of being a Chinese undercover agent tied up his hands and tried to beat him up. 

The man was pictured with his hands bound with cable ties, lying in a fetal position on the ground surrounded by a crowd of protesters as demonstrations continued at the airport for a second day and turned tense late Tuesday.

Some tried to kick and hit him while others tried to hold the crowd back.

Protesters said they detained him because he wore a press vest and claimed to be a reporter, but a mainland Chinese ID card was found in his belongings. 

The chaotic situation eventually ended when protesters allowed ambulance workers to take the man away on a stretcher. 

Pro-democracy protesters have been sensitive to police infiltration after activists were arrested by officers dressed just like them. Police have acknowledged that they use decoy officers in some operations. 

At least three concerts by overseas performers have been canceled in Hong Kong as protesters forced the city's airport to suspend operations for a second day. 

K-pop star Kang Daniel and Scottish band CHVRCHES both announced Tuesday that they are calling off upcoming events. American singer-songwriter Alec Benjamin canceled an upcoming concert late Monday. 

Kang's management office said the cancellation of a fan meeting scheduled for Sunday was because of safety concerns related to the protests, while CHVRCHES blamed "unforeseen circumstances." 

The airport protests are the latest escalation in a summer of demonstrations aimed at what many in Hong Kong see as an increasing erosion of their freedoms. 

A reporter from China's Global Times was seized by demonstrators at Hong Kong airport on Tuesday but was rescued by police, the newspaper's editor in chief said.

"GT reporter Fu Guohao has been rescued by police and sent to the hospital. We're still learning about his injury conditions", Hu Xijin said in a tweet.

Global Times is a tabloid published by the Ruling Communist Party's People's Daily.

In an earlier tweet, Mr Hu had attached a video and said his reporter was tied up by demonstrators.

Protesters had earlier detained a man they believed was an undercover police officer, after finding a mainland China card in his bag.

They fastened his wrists and poured water over his head. The man was eventually taken out of the airport by emergency services.

Hong Kong leader Carrie Lam earlier defended law enforcement actions after protesters prompted an airport shutdown with calls to investigate alleged police brutality.

Ms Lam told reporters on Tuesday morning that dialogue would only begin when the violence stopped. She reiterated her support for the police and said they have had to make on-the-spot decisions under difficult circumstances, using "the lowest level of force."

The embattled leader was speaking before further violence broke out at the airport. 

Pro-democracy protesters in Hong Kong want her to resign but Ms Lam has said she intends to remain in her post.

Most protesters and police have left Hong Kong Airport after a second day of demonstrations that caused mass flight cancellations at the busy transport hub. 

Riot police clashed with pro-democracy protesters outside the building earlier on Tuesday night. Officers armed with pepper spray and swinging batons tried to enter the terminal, while protesters used luggage carts to barricade entrances. 

Hundreds of flights were cancelled and passengers have been forced to stay in the city while airlines tried to find other ways to get them to their destinations. 

The airport disruptions are an escalation of a summer of demonstrations against what some in Hong Kong see as an increasing erosion of freedoms. The protests have in recent weeks turned to focus on police brutality against demonstrators. 

Dominic Raab, the UK's foreign secretary, has condemned the violence in Hong Kong.

"Concerning to see what's happening in Hong Kong and the worrying pictures of clashes between police & protesters at the airport," Mr Raab said in a tweet posted on Tuesday evening.

"As I said to Carrie Lam during my call last week, we condemn the violence & encourage constructive dialogue to find a peaceful way forward."