HONG KONG — Anti-government protesters clashed with Hong Kong riot police on Tuesday, crippling the airport for the second straight day and targeting a potent symbol of the city’s position as a global center of commerce and finance that is essential to China.

The mass protests have forced the airport to suspend check-ins, creating long delays for passengers and forcing airlines to cancel hundreds of flights over the past two days. After a chaotic night, check-ins resumed on Wednesday morning, but the airport warned that flights would be rescheduled, and Hong Kong’s flagship carrier said there could be “further flight disruptions at short notice.”

[How the airport that symbolized Hong Kong’s global stature became a hub of its unrest.]

The protests at the airport have been deeply tactical, as the largely leaderless movement strikes at a vital economic artery. Hong Kong International Airport, which opened in 1998, a year after China reclaimed the territory from Britain, serves as a gateway to the rest of Asia. Sleek and well-run, the airport accommodates nearly 75 million passengers a year and handles more than 5.1 million metric tons of cargo.