BEIJING (AP) – Chinese avant-garde artist Ai Weiwei said Saturday authorities would keep him under house arrest for at least another 24 hours 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.
“I'm under house arrest to prevent me from going to Shanghai. You can never really argue with this government,” Ai, 53, said.
“They've told me I would be held until midnight Sunday and I would be prevented from leaving before then,” he said.
Ai said the men refused to identify themselves and it wasn't clear who gave the order to detain him. On Saturday afternoon, three plainclothes officers watched outside Ai's home in an artists' colony on the eastern edge of the city, but did not prevent an Associated Press Television reporter from entering to interview him.
Ai, who is also an architectural designer, said he had been invited by the head of Shanghai's suburban Jiading district to build a studio on a plot of farmland containing a derelict warehouse. He said he was initially reluctant, but eventually agreed and spent two years designing and building the studio, only to receive notice in July that the building was an illegal structure and would be knocked down.