HONG KONG — Hong Kong protesters on Sunday shifted their focus back to the city’s airport, hindering access to one of the world’s busiest international transit hubs, prompting clashes with police, transportation snarls and confusion.

Their action, a “stress test” to force the government to respond their demands after months of sustained demonstrations, caused airlines to delay and cancel flights, and left passengers with few ways to get to the airport. Many walked from nearby bus terminals.

Organizers said they hoped to hold similar actions every weekend if the government does not give in to their demands.

“The airport is vital to the economy of Hong Kong,” said one of the organizers of Sunday’s action, speaking to reporters over the Telegram secure messaging app. “The most impactful way to express our five demands is to go to the airport.”

By the afternoon, an express train connecting the city to Hong Kong International Airport was suspended — first because of a decision from authorities, and later because demonstrators had flung objects on the track. Protesters began marching to a subway stop close to the airport, blocking a major access road.

The rallies followed intense clashes between protesters and police in Hong Kong on Saturday, a day that ended with fear and violence at subway stops when riot police stormed trains filled with commuters going about their evening, swinging batons and making arrests.

On Sunday, police were waiting at the piers for ferries from Lantau Island, where the airport is located. They stopped and searched those who got off the boats, collected bags of evidence and wrote down identification numbers.

With other public transportation largely shut down, hundreds walked along the highway for hours across Lantau Island back toward Hong Kong Island. Eventually, they were met at a toll plaza by dozens of volunteer drivers who answered calls put out on Telegram to assist demonstrators.

After 13 straight weekends of protest, the rupture between Hong Kong police and civilians appears to be solidifying, with no end in sight to the crisis. The government refuses to make concessions, and protesters have been undeterred by mass arrests and police use of force.

Hong Kong International Airport has been the focus of previous demonstrations. Protests against a proposed law to allow extraditions to mainland China have attracted widespread support across the semiautonomous Chinese territory. Hong Kong police marching through the airport on Sunday were met with jeers.

Later Sunday, protesters entered a metro station near the airport and defaced it. They smashed glass panes, flooded the station and sprayed graffiti reading “communist rail trash” and “glory to Hong Kong.” Protesters also set barricades and roadblocks on fire.