NEW YORK - The Chinese government should immediately release the artist and outspoken critic Ai Weiwei and end its arbitrary crackdown on dissent, Human Rights Watch said today. Ai was arrested at Beijing airport on the morning of April 2, 2011, as he was about to board a flight for Hong Kong. Despite considerable domestic and international attention, the Chinese government has refused to disclose where he is detained or the reasons for his arrest. Incommunicado arrests are often the prelude to criminal prosecutions, Human Rights Watch said. "The arrest of Ai Weiwei reflects a new escalation in the current and already severe crackdown," said Sophie Richardson, Asia advocacy director at Human Rights Watch. "Only sustained international pressure can help Ai Weiwei now." On April 6, in what can be read as the first official acknowledgment of Ai's arrest, a newspaper article in the state-run Global Times announced that Ai would "pay a price" for being an activist and that "the law would not concede" to his criticisms of the government.

The government's detention of Ai Weiwei appears to have been carefully planned. On the day he was arrested, Beijing public security officers raided his art studio in the suburbs of Beijing and took eight members of his staff, his wife Lu Qing, and a lawyer friend of Ai's, Liu Xiaoyuan, in for questioning; they were all released later that day. The police seized computers, hard-drives, and other items. State media were instructed not to report on the case, and all references to Ai Weiwei's arrest were censored on internet and popular micro-blogging services such as Weibo, a Twitter clone.

Under Chinese law, the police can hold an individual for up to three days before deciding whether to release him or apply to the prosecutors for an arrest warrant. But invariably the police manipulate exception clauses that allow for up to seven days' and, in limited circumstances, up to 30 days' detention. Police also routinely prevent lawyers from meeting their clients in detention despite legal provisions guaranteeing such access.

Ai's lawyer, the prominent Beijing lawyer Pu Zhiqiang, has so far been unable to see his client, or even to get formal notification of his arrest. Approval of arrest by the prosecutors, a matter of routine in most cases, usually guarantees later indictment, conviction, and punishment, which typically includes a prison sentence. The 2010 Nobel Peace Prize laureate, Liu Xiaobo, was detained for a year before he was sentenced in December 2009 to an 11-year term of imprisonment for a series of articles published overseas.

The arrest of Ai, one of the most celebrated Chinese artists, who is currently exhibiting at Tate Modern in London, has prompted a reaction from several foreign governments, with German Foreign Minister Guido Westerwelle calling on China for an "urgent explanation" of his fate. British Foreign Secretary William Hague has called on the government to "urgently clarify Ai's situation and well being." The European Union delegation in Beijing, members of the European Parliament, and the Australian government have also expressed concern. US State Department spokesperson Mark Toner said on April 4 that the government was "deeply concerned."