BEIJING (AFP) - China on Thursday warned the international community it had "no right to interfere" in the case of outspoken artist Ai Weiwei, who has been detained for investigation of unspecified economic crimes. Foreign ministry spokesman Hong Lei confirmed a state media report that Ai, an avant-garde artist taken into custody in Beijing on Sunday as the government pursues a heavy crackdown on dissent, was the subject of a police probe. Western governments and rights groups have lined up in support of Ai, who was detained while trying to board a flight to Hong Kong and has not been heard from since, but Beijing signalled it would not tolerate criticism from abroad. "Ai Weiwei is under investigation on suspicion of economic crimes," Hong told reporters during a briefing, refusing to comment on the nature of the alleged crimes. "It has nothing to do with human rights or freedom of expression," he said, in the first official Chinese comment on Ai's case. "Other countries have no right to interfere," added Hong, who later refused to answer further queries on Ai and abruptly cut the briefing short when the questions continued. Ai, who was born in 1957, is merely the latest of dozens of activists and government critics rounded up following online calls for demonstrations in China to emulate the "Jasmine" protests that have rocked the Arab world. The United States, France, Germany and Britain have joined Amnesty International and other groups in calling for Ai's release, with US ambassador Jon Huntsman defending the artist in a Shanghai speech on Wednesday.