By Michael Bristow
BBC News, Beijing
Fears about ethnic tension could be motivating China's censorship efforts
A few days before the start of this year's Melbourne International Film Festival its executive director received an "audacious" telephone call.
An official from China's consulate in the city called him to "urge" the festival to withdraw a film about the Chinese activist Rebiya Kadeer.
Beijing then tried to persuade the organisers of the Frankfurt Book Fair not to allow two Chinese writers to attend an event.
China says it does not interfere in the internal affairs of other countries.
But some see these acts as an attempt by China to use abroad the tough censorship measures it constantly employs at home.
Intimidation and threats
Richard Moore, the Melbourne festival's executive director, said he was astonished to receive the call from the city's Chinese consulate.
"It came down to [the consular official] saying we need to justify our decision to include the film in the programme. It was a remarkable display of confidence and arrogance," he said.
The festival decided to ignore the advice and go ahead with the film - about an activist who campaigns for better rights for China's Uighur minority - but that did not end the issue.
The festival organisation was subjected to an intense campaign of threats, intimidation and disruption, although it is not clear who - if anyone - orchestrated the campaign.
The festival e-mail address received insulting messages, there were waves of annoying phone calls and the fax machine was jammed with callers.
Chinese officials objected to writer Dai Qing speaking in Frankfurt
Some notes to the organisers contained messages threatening Mr Moore's family.
Internet hackers managed to break into the festival's online booking site, making it appear that session tickets had been sold out.
Hackers also managed to post a Chinese flag on the main website and Chinese film-makers withdrew their movies from the festival.
The film at the centre of the controversy - called The 10 Conditions of Love - was finally shown at a larger venue, partly because the publicity surrounding the row increased interest.
Its subject, Rebiya Kadeer, was also invited to take part in a talk at the festival, which took place in July and August.
But Mr Moore admits that the event organisers will look hard at how to showcase controversial films at future festivals.
The Chinese government was just as direct with the organisers of the Frankfurt Book Fair, an annual event that bills itself as a "worldwide marketplace for ideas".
China was the guest of honour at this October's fair and Beijing funded a series of events to showcase its literature and culture.
But Chinese officials were angry when they found out writers Dai Qing and Bei Ling had been invited to a symposium connected to the fair.
According to Juergen Boos, the fair's director, China asked the organisers to ban the writers, a request they initially agreed to carry out.
The two Chinese writers were then allowed to speak at the symposium, but when they stood up to make a speech some of the Chinese delegation left the room.
"We did not come to be instructed about democracy," a former Chinese ambassador told the event organisers.
China often asks foreign governments and organisations not to do something that it perceives to be against its interests. It recently complained to Japan when Tokyo allowed Ms Kadeer to enter the country.
But it says this does not contravene its policy of non-interference.
"I believe the Chinese government has not violated the principle of interfering in others' internal affairs," said Chinese Foreign Ministry spokesman Ma Zhaoxu recently in response to a question about this policy.
But writer Dai Qing, who is also an environmental campaigner, believes China's increasing economic muscle has emboldened the country's leaders.
"China is using its economic influence to threaten its trade partners in order to censor what they don't like," she said.
David Zweig, of the Hong Kong University of Science and Technology, is not so sure the Chinese are doing it from a position of strength.
"Sometimes we cannot tell whether it's confidence or concern," said Mr Zweig, the director of the Centre on China's Transnational Relations, based at his university.
He said China's attempts to prevent Ms Kadeer from speaking publicly, for example, could be linked to concerns about ethnic tension in Xinjiang, where most Uighurs live.
Hundreds of Uighurs rioted in July, killing scores of Han Chinese people.
Mr Zweig added that there could also be another reason behind the pressure - the Chinese government and its people are often quick to take offence at opinions they do not like to hear.
And he said ordinary people were sometimes more sensitive than officials - forcing the government to take a tougher stance internationally.
That could be why China is now trying to censor critical opinions abroad.