Hong Kong International Airport has cancelled departing flights, as anti-government protests in its main terminal continue for a fourth day. Thousands are gathered at the airport - which is one of the world's busiest. In a statement, officials said operations had been "seriously disrupted" by the public assembly. Many of those protesting are critical of the actions of police, who on Sunday were caught on film firing tear gas and non-lethal ammunition at close range. Some protesters are wearing bandages over their eyes in response to images of a woman bleeding heavily from her eye on Sunday, having reportedly been shot by a police projectile. In a statement on Monday, Hong Kong's Airport Authority said they were cancelling all flights that were not yet checked in. More than 100 flights scheduled after 18:00 local time (10:00 GMT) will now not depart. Officials have advised members of the public not to travel to the airport but said arrivals already heading into Hong Kong would be allowed to land. About 75 million passengers passed through the airport - which is a major international transit hub - in 2018. "The information I got before we came in was that in the airport passenger terminal building there are over 5,000 protesters," Kong Wing-Cheung, senior superintendent of the police public relations branch, said. It is unclear if police will try to move in to disperse the protesting group. Hong Kong's mass demonstrations and unrest show no sign of abating, more than two months after they were sparked by a controversial extradition bill. Beijing officials have strongly condemned Sunday's violence and linked violent protesters to "terrorism".