BEIJING (AP).- Chinese avant-garde artist Ai Weiwei said Saturday that he has been placed under house arrest to prevent him from attending a party commemorating the forced demolition of his newly built studio in Shanghai.

Ai, who has become known as much for his social activism as his art in recent years, was planning to fly to the Chinese financial hub for Sunday's celebration, but people he suspects were police told him Friday that he would not be permitted to leave his Beijing home.

Speaking by telephone, Ai said the men refused to identify themselves and it wasn't clear who gave the order to detain him.

On Sunday afternoon, three men in plainclothes were ensconced in a minivan with no license plates that was blocking the entrance to Ai's home in an artists colony on the eastern edge of the city.

"I'm under house arrest to prevent me from going to Shanghai. You can never really argue with this government," Ai said.

Ai was courted by the communist government as a cultural ambassador before his advocacy on behalf of social activists apparently made him a target of internal security.

He was a consultant for the futuristic Bird's Nest stadium at the Beijing Olympics before souring on the event. He was later beaten and detained while attempting to attend the trial of an advocate for victims of the devastating 2008 earthquake in the southwestern city of Chengdu.

Ai has exhibited and contributed to projects throughout Europe and the United States, and an installation of his involving 100 million porcelain sunflower seeds is currently on display at the Tate Modern gallery's famed Turbine Hall in London.

Such notoriety had prompted Shanghai's government to invite him to open a studio to give the city added cultural cachet, but his subsequent activism appears to have turned its notoriously cautious bureaucrats against him.

His studio had hardly been finished when Ai said he was served with a notice telling him to have it knocked down.

He had planned to commemorate the event with a party at the studio on Sunday catered with river crabs — a Chinese homonym for the government's catch phrase of "harmonious." Critics sarcastically use the term to describe policies such as censorship and the demolition of working class homes to make way for flashy new developments.

The gathering has been canceled, although Ai said many would-be attendees still planned to visit the space on Sunday.

Ai's detention comes amid a crackdown on China's small, embattled dissident community prompted by the awarding last month of the Nobel Peace Prize to imprisoned Chinese dissident writer Liu Xiaobo.

Liu's wife and a number of friends and colleagues have been held at police stations or placed under detention in their homes to prevent them from expressing their support. That treatment that is expected to continue at least until the award ceremony in Oslo, Norway, on Friday.

Beijing was enraged by the awarding of the prize to Liu, and has responded by issuing a hail of diatribes denigrating Liu, the Nobel Peace Prize committee, and the West in general and pressuring foreign countries not to send representatives to attend the award ceremony.


Copyright 2010 The Associated Press.