China's best-known artist Ai Weiwei has been detained at Beijing airport this morning and police have surrounded his studio in the capital.
The 53-year-old, who designed the Olympic Bird's Nest stadium, has been an outspoken critic of the government. Although he has previously experienced harassment by officials, he appeared to be relatively protected by the status of his late father, a renowned poet, and his high international profile; last year, he created the Sunflower Seeds installation for Tate Modern.
Ai was due to fly to Hong Kong for business this morning, but was detained at immigration on his way out of Beijing. An officer told an assistant who was travelling with him that the artist had "other business" and could not board the plane.
Between 15 and 20 uniformed and plain clothes police surrounded his studio in Caochangdi, in the north of the capital, and more were believed to be searching it. Power to the neighbourhood was cut off.
Men who appeared to be plainclothes police grabbed the phone of a Guardian journalist who took a photograph of the scene and deleted the image. A uniformed officer told the reporter: "You are not allowed to be on this street. You must leave."