HONG KONG — Protesters began issuing apologies on Wednesday for causing disruptions at the Hong Kong airport, as fallout from scenes of violence and chaos there, along with a court injunction, threatened to eliminate the transportation hub as one of their most effective venues for demonstrations.Protests led the airport, one of the world’s busiest, to suspend check-ins for two days in a row this week, causing hundreds of flight cancellations and delivering a blow to a symbol of Hong Kong’s efficiency and economic prominence.The airport said Wednesday that at 2 p.m. it would begin limiting terminal access to ticketed passengers and airport workers.Demonstrations at the airport began Friday and stayed peaceful for days, as protesters made their case to many of the 200,000 passengers it handles each day. When disruptions to flights began on Monday, some travelers complained, but others said the movement to protect Hong Kong’s civil liberties was more important than their inconvenience.But uglier scenes developed on Tuesday, as a few scuffles broke out between protesters and travelers, who for the first time were being blocked from the departure gates. In the evening, with tensions rising, some protesters surrounded, tied up and beat two men from mainland China — one of whom they suspected of being a security officer, while the other proved to be a reporter for a Communist Party-owned newspaper.Riot police officers briefly entered the front doors of the airport, and one drew but did not fire his pistol after a scuffle with protesters.[Here’s a guide to what prompted the Hong Kong protests and how they evolved.]On Wednesday, protesters seemed well aware of the negative image they had presented. “We apologize for our behavior but we are just too scared,” read one post on a messaging channel used by protesters, which gained wider distribution on other social media. “Our police shot us, government betrayed us, social institutions failed us. Please help us.”“Please accept our sincere apology to all travelers, press reporters, paramedics,” read another post. “We will learn from our mistakes. Please give us a second chance to prove ourselves that we can be better.”The protests — which began over a now-suspended plan to allow extraditions to mainland China, but have grown to include calls for more direct elections and investigations into the police’s use of force — have been largely leaderless. A march in June drew as many as two million people, according to organizers, and thousands have continued to join near-daily demonstrations.No single voice speaks for all the participants. Some embrace nonviolence, while others say confrontation is needed because the government has ignored the calls of peaceful protesters. Thus far, protesters have embraced overall messages of solidarity, despite differing beliefs about the best strategies.The violence at the airport quickly received prominent coverage in mainland China’s state media, which, after initially ignoring the protests, has become laden with strident criticism and misinformation about them.“What a shame for Hong Kong,” People’s Daily, the ruling Communist Party’s main mouthpiece, said in a message on social media.A quote from the reporter who was beaten, “I support the Hong Kong police,” became a top trending term on Weibo, a Twitter-like platform. The reporter, Fu Guohao, is doing well and was not seriously injured, said Hu Xijin, editor in chief of Global Times, the nationalist tabloid that employs him.“It’s the utmost disgrace for the protesters to treat a reporter like this,” Mr. Hu said in a message. “This shows that they have lost their rationality. Hatred has muddled their minds.”A spokesman for the Hong Kong and Macau Affairs office, the Chinese government agency that deals with the two cities, denounced the airport violence in a statement on Wednesday, calling it “conduct close to terrorism.”Some protesters said that recent police tactics, including undercover officers apparently dressing as protesters to make arrests, had contributed to a sense of fear. Video of one recent arrest showed officers, one in the black T-shirt and yellow helmet commonly worn by demonstrators, grinding a protester’s bloodied face into the pavement.“We hope everyone, including travelers in and out of Hong Kong, would also understand the stress, the panickiness, the suspicion, the restlessness involved in the crowd at the airport ever since the Hong Kong police force’s admission of masquerading a certain number of officers as protesters with the aim of getting them arrested,” Claudia Mo, a pro-democratic legislator, said at a news conference on Wednesday.The Hong Kong Airport Authority said it had obtained an interim injunction to prevent interference with airport operations. It was not clear what immediate effect, if any, the injunction would have on the protests. Similar orders were used to allow workers, under the supervision of police officers and bailiffs, to dismantle protesters’ encampments during the large pro-democracy demonstrations that swept Hong Kong in 2014.On Wednesday morning, a few dozen protesters remained in the airport, sitting in an area designated for protests. Parts of the arrivals halls were still covered with posters carrying their messages, which have focused in recent days on complaints about the police’s use of force.“We are not rioters, we just love HK too much,” read one sign.