Hong Kong airport authorities on Monday cancelled all flights after thousands of protestors occupied the main terminal building as the demonstrations continued for a fourth straight day in the airport, Bloomberg reported.

“Airport operations at Hong Kong International Airport have been seriously disrupted as a result of the public assembly at the airport today,” the airport said in a statement. “All check-in service for departure flights has been suspended. Other than the departure flights that have completed the check-in process and the arrival flights that are already heading to Hong Kong, all other flights have been canceled for the rest of today. Members of the public are advised not to come to the airport.”

Authorities called the protests illegal and dangerous, and highlighted their impact on the economy and residents’ daily lives, Reuters reported.

The protestors packed the arrival area where they had gathered for a three-day sit-in that was originally planned to end on Sunday night.

The police also fired tear gas and beat demonstrators on Monday, Al Jazeera reported. “It’s not just the water cannon,” one of the protestors, Steven Ng was quoted as saying by Reuters. “The police are continuing to use all sorts of weapons to challenge the bottom line of Hong Kong people with their weapons...All Hong Kong people with a conscience can see this clearly.”

Scores of protestors were arrested after being beaten with batons by police. More than 600 people have reportedly been arrested since the unrest began more than two months ago.

The authorities also put on a demonstration of an anti-riot water cannon. Global rights group Amnesty International condemned this. “Water cannons are not a toy for the Hong Kong police to deploy as a sign of strength,” Man-kei Tam, the group’s Hong Kong director, said in a statement. “These are powerful weapons that are inherently indiscriminate and have the potential of causing serious injury and even death.”

The protests had initially been organised to oppose a bill that would have allowed extraditions to China. The protests have now continued for ten consecutive weekends and evolved into a backlash against the city’s government and its political masters in Beijing. The government has refused to accept any of the protestors’ main demands, which include a complete withdrawal of the extradition bill besides an independent inquiry into the use of excessive police force against the demonstrators. They are also demanding the resignation of the city’s leader Carrie Lam.

Beijing has claimed that criminals and agitators are stirring violence, encouraged by interference from foreign powers including Britain.