By Austin Ramzy

New York Times

HONG KONG >> Thousands of demonstrators took to the streets of Hong Kong on Friday in an annual march calling for greater democracy, but one expected leader of the event was missing: an outspoken bookseller, who canceled out of fears for his safety, a legislator said.

The bookseller, Lam Wing-kee, went public in June about the five months he spent in detention in mainland China, saying that he had been held in isolation in an effort to force him to disclose the names of mainland buyers of gossipy political books published in Hong Kong by the business that employed him.

The case of Lam and four other men connected with the publisher, Mighty Current Media, has stoked concerns in Hong Kong about the potential breakdown of the rule of law in the semiautonomous territory because of growing influence from the mainland.

Lam had said that he would lead the march that started in Victoria Park on Friday, but he pulled out hours before it began. Albert Ho, a lawyer and legislator in Hong Kong, said that Lam had indicated that he had been followed over the previous two days by people he did not recognize.

“He is increasingly concerned about his personal safety, so he made a personal decision not to attend this July 1 march,” Ho said. “We have already notified the police, and Lam has already found a safe place to live.”

July 1 is a holiday in Hong Kong honoring the 1997 handover of the former British colony to Chinese control. In 2003, half a million people marched on the holiday to vent grievances over the handling of the SARS epidemic and over a government effort to pass a domestic security law.

Since then, the turnout has served as a barometer of public discontent. In 2015, the protest was one of the smallest in recent years, which organizers attributed to fatigue over the Occupy movement, when in the fall of 2014 protesters took over several crucial roadways for weeks to demand greater public participation in the nomination of candidates for Hong Kong’s top political office, the chief executive. Those efforts and calls by the protesters for the resignation of the current chief, Leung Chun-ying, were unsuccessful.

The Civil Human Rights Front, the group that organized the march on Friday, said 110,000 people attended. The Hong Kong police said the peak number was about 20,000.

Many protesters on Friday said they were especially concerned about the case of the five men associated with Mighty Current Media, who were detained by the mainland police last year. One man, Gui Minhai, remains in custody. Although the others have returned to Hong Kong and said little about their experiences, Lam said that he felt compelled to speak out.

In the days after a dramatic news conference in which Lam described his detention, however, some of his former colleagues and a woman who said she was his girlfriend questioned his account in interviews with a newspaper in Hong Kong. His decision not to participate in the march indicated a potential erosion of freedom of speech in the city, said Ho, the lawyer. But he added that most residents would not be afraid to protest.

One of the demonstrators on Friday, Chow Yu-lung, 63, fled to Hong Kong from Guangdong province in mainland China when he was 10. He said he joined the march because he felt the local government was putting the interests of the authorities in Beijing before those of its residents.

“We risked our lives and fled to Hong Kong for freedom in the 1960s,” he said, “and now Beijing wants to take it back from us?”

The plans for the protest revealed something of the growing ideological divide within the pro-democracy camp in Hong Kong. Some people, particularly younger residents, say it is more important to focus on the city itself, as opposed to broader questions of whether China’s central government will ever liberalize. They have called for increased autonomy for Hong Kong, and others have argued for independence from China.

That contingent was expected to appear in force at a separate protest on Friday evening outside the mainland government’s liaison office. But members of that group had not filed for official approval for the rally, which suggested the possibility of confrontations with the police.

Global Times, a newspaper owned by the Chinese Communist Party, sharply criticized the demonstrations in an editorial on Friday, saying that the anticipated participation of people like Lam showed a disregard for China’s central government.

“The Hong Kong opposition always demands the central authorities not interfere with Hong Kong’s internal affairs,” the editorial said. “But now they have an attitude of openly challenging the mainland’s legal and political situation. This is dangerously misguided.”