This year's Beijing Independent Film Festival never even got to open, said its artistic director, Wang Hongwei, and executive director Fan Rong of the Li Xianting Film Fund.
Li Xianting, founder of the fund and a film critic, posted memos in social media over the past week saying that state security personnel had been pressuring him to cancel the festival and that he had come under police surveillance.
Both Wang and Fan verified the authenticity of Li's posts.
The festival, which began in 2006 and was scheduled to run through Aug 31, has encountered obstruction in past years, but this is the first time it has been shut down completely, a sign that Beijing is tightening ideological controls under President Xi Jinping, said Chris Berry, professor of film studies at King's College London in England.
"It's very clear that the Xi Jinping regime is determined to control the ideological realm, which has not been emphasised so much for a long time," he said.
But Berry said authorities' hostility to the Beijing event did not mark the end of independent filmmaking, as Chinese filmmakers have found more venues in an increasingly diverse environment.
The boom in the mainstream movie industry, the rise of galleries that curate artwork based on moving images, and the internet all have provided new opportunities, he said.
"Let's not be totally pessimistic," Berry said.
Police in the Beijing suburb of Songzhuang, where the event was supposed to open, said on Saturday that they were unaware that the festival had closed. But security was tight at the festival site, with about two dozen men blocking the area and preventing around 30 film directors and members of the public from entering.
The men, claiming to be villagers, tried to stop anyone from photographing or videotaping the scene, and in a scuffle, broke a video camera an Associated Press journalist was operating and took away the cellphone of another AP journalist. The phone was later returned.
Started as a film forum in 2006, the festival over the years has grown to be one of the most important events for China's independent films, but also has attracted the attention of authorities eager to regulate free speech.
In 2012, electricity was cut off shortly after the festival opened, but organisers still managed to show some new movies. Last year, the festival went on, although public screenings were banned.
Li said that Fan and Wang were taken away by Songzhuang police on Friday afternoon and forced to sign a letter of promise to cancel the festival, before being freed five hours later.
He said employees of the film fund were also informed that the electricity to the office would be cut off starting on Saturday.