efe-epaBy Shirley Lau Hong Kong

All outbound flights from Hong Kong have been canceled for the second day in a row as protesters block the departure area of one of the world's busiest airports.

"Airport operations at Hong Kong International Airport have been seriously disrupted, all departure flights have been cancelled," read a statement posted on the Airport Authority's website at 5pm.

"All passengers are advised to leave the terminal buildings as soon as possible. Affected passengers please contact their respective airlines for flight arrangement."

Over 1,000 protesters in Hong Kong returned to the airport Tuesday afternoon for a sit-in for the fifth consecutive day, while the airport has grounded over 360 flights for the day, struggling to clear flight backlog caused by sweeping flight cancellation the day before.

Meanwhile, healthcare professionals also made a rare move to stage sit-ins at 13 public hospitals to protest excessive use of force by police in the recent wave of protests.

A total of 173 outgoing flights and 157 inbound flights are still listed were canceled from 7.00 local time (23.00 GMT) through midnight Tuesday, as indicated by the website of Hong Kong International Airport Tuesday afternoon.

This came a day after all outbound flights and over 70 inbound flights were canceled amid a mass rally staged by thousands of anti-government protesters.

The Hong Kong Airport Authority said earlier that it hoped flights would resume at 6.00. However, as it takes time to handle the flight backlog at one of the busiest airports in the world, hundreds of travelers remain stranded.

Then at around 13.00 local time (5.00 GMT), hundreds of protesters started arriving at Terminal 1 of the airport to continue their campaign to draw international travelers' attention to their home city's ongoing political crisis and alleged police brutality.

The activists, many clad in black, chanted slogans, sang the Les Miserables song "Do you hear the people sing" and tried to engage travelers in conversations. Some frustrated travelers who had been stranded for hours criticized the protesters' action; others were more understanding.

Posters and signs could be seen everywhere, with messages such as "Sorry for any inconvenience, we have no choice" and "They took a nurse's right eye", referring to an incident Sunday night where a young woman, believed to be a nurse, was allegedly shot by a police projectile during a street protest.

The shooting incident, as part of the police's unusually heavy-handed operation to clear protests in various districts that night, has enraged many Hongkongers and was one leading factor prompting over 5,000 protesters to return to the airport Monday, extending a planned three-day sit-in at the airport that was supposed to end Sunday night.

The police clearance operation Sunday courted widespread controversy also because riot police shot teargas into two metro stations - violating the factory instruction of no-usage indoor - and fired non-lethal ammunition at protesters from less than two meters. A police officer was also filmed putting a sharp bamboo stick into the backpack of a young protester when he was under arrest, drawing allegations of planting fake evidence.

In response to the alleged police brutality, hundreds of staff members of 13 public hospitals across the territory respectively staged a sit-in at their hospitals at around noon Monday. Many donned an eye patch in a show of support for the young woman who was shot in the eye.

Speaking to a group of medical practitioners joining the protest, Dr Chan Chi-wai, former director of the department of orthopaedics of United Christian Hospital, said: "You and I are stakeholders in Hong Kong. We have to defend Hong Kong. Although we are disappointed, but don't lose hope. Don't give up."

China's civil aviation authority said Tuesday that it will increase transfer capacity at airports on the Pearl River delta (which includes cities such as Guangzhou, Shenzhen and Zhuhai) to cope with the disruption of flights between China and Hong Kong.

Meanwhile, Hong Kong's top leader Carrie Lam also gave Hong Kong protesters a piece of her mind Monday morning when meeting the press.

She criticized the sit-in for paralyzing the airport and also condemned protesters for jeopardizing Hong Kong's rule of law in the name of freedom and justice in recent protests.

"I urge everyone to set aside differences, calm down and take a minute to think, to look at our city, our home. Do we really want to push it into an abyss where all will be destroyed? For now, the only thing to do is to resist violence, defend the rule of law and restore order," she said.

Lam also defended the police force, saying it had been going through an "extremely difficult" time over the past two months. She brushed aside a journalist's question on whether she had the autonomy to announce a formal withdrawal of the controversial extradition law, which sparked the current political crisis.

The proposed law, which would have enabled fugitives to be extradited from Hong Kong to mainland China, was declared "dead" by Lam. But the civil movement against it has since morphed into a broader anti-government movement seeking to reverse a general decline in freedoms.EFE-EPA