Hong Kong International Airport, one of the world's busiest terminals, saw further disruption Tuesday with all check-in services being suspended in the afternoon due to pro-democracy demonstrations.
"Terminal operations at Hong Kong International Airport have been seriously disrupted as a result of the public assembly at the airport today," Airport Authority Hong Kong said in statement. It said that check-in services for departing flights had been suspended since 4:30 p.m. local time and urged customers not to come to the airport.
The authority added that "other departure and arrival flights for the rest of the day will continue to operate, and airlines will provide arrangements for passengers who have not completed the departure process."
Hong Kong-carrier Cathay Pacific warned in a separate statement that there was the potential for further flight disruptions at short notice.
Around 5,000 anti-government protesters had been demonstrating at the airport for a fifth day. On Monday afternoon, all flights were canceled due to the disruption but reopened early Tuesday morning. Hong Kong International is the eighth-busiest airport in the world and handles over 72 million passengers a year, according to the latest statistics by Airports Council International.
The increasingly violent protests since June have plunged the Asian financial hub into its most serious crisis in decades and are one of the biggest popular challenges to Chinese leader Xi Jinping since he came to power in 2012.
The movement began more than two months ago in opposition to a bill allowing extradition to the mainland. Despite the intense police response and the toughening stance from China, it still seems to enjoy broad support in the city of more than 7 million people. The rallies have snowballed into a democracy movement, with some even demanding full autonomy from Beijing.
The unrest in Hong Kong — a former British colony that was returned to Chinese rule in 1997 — has also frequently crippled its transportation system.
Chinese propaganda outlets warned on Tuesday that protesters in Hong Kong are "asking for self-destruction," as they released a video showing military vehicles amassing near the border of the city.
—Reuters and CNBC's Grace Shao contributed to this article.