Chinese authorities have blocked an annual independent film festival from opening, seizing documents and films from organisers and hauling away two event officials in a sign that Beijing is stepping up its already tight ideological controls.

Li Xianting, a film critic and founder of the Li Xianting Film Fund, the organiser of the Beijing Independent Film Festival, said police searched his office and confiscated materials he had gathered over more than 10 years.

 The festival's artistic director, Wang Hongwei, was  briefly detained by police [AP]

Li and the festival's artistic director, Wang Hongwei, were detained by police on Saturday night but later released, according to their supporters.

The festival, which began in 2006, has seen severe police obstruction over the past few years, but this year's crackdown is far more serious, Wang said.

"In the past few years, when they forced us to cancel the festival, we just moved it to other places, or delayed the screenings," he told the AP news agency. 

"But this year, we cannot carry on with the festival. It is completely forbidden."

Security was tight at the site of the festival in the capital's Songzhuang suburb, AP reported, with about two dozen men blocking the area and preventing around 30 film directors and members of the public from entering.

Hu Jie, a movie director who travelled from the eastern city of Nanjing to attend the festival, was upset at the cancellation.

"The audience for my films is already quite small, perhaps because I make documentaries that talk about history," Hu said.

"If one of the rare film festivals, like the Beijing Independent Film festival, is shut down, then it will be very difficult for us to survive as filmmakers."

Started as a film forum, 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. The government is concerned that such events may become a platform for ideas that challenge the ruling Community party's ideology.

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.

Source: Associated Press