Western powers and rights groups have expressed anger and concern over the fate of outspoken Chinese artist and social critic Ai Weiwei, who has disappeared into policy custody.
The United States, France, Germany and Britain joined Amnesty International and other groups in calling for the release of Ai, who was detained on Sunday at Beijing's airport as he prepared to board a flight abroad.
His wife and lawyer both told AFP on Tuesday that they still had no news about the whereabouts or situation of the artist, whose outspoken criticism of China's ruling Communist Party has landed him in hot water in the past.
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Beijing police and China's foreign ministry refused to comment on the disappearance of the 53-year-old.
The artist's detention comes amid a huge clampdown on dissent apparently triggered by anonymous online calls for people to gather every Sunday around China in peaceful protests, aimed at emulating unrest rocking the Arab world.
Scores of dissidents, activists and rights lawyers have been rounded up in recent weeks, with many placed under house arrest or disappearing into police custody. Some have even been formally charged with "inciting subversion."
The EU ambassador to China expressed concern Tuesday about the "increasing use of arbitrary detention in China" following Ai's disappearance.
"We call on the Chinese authorities to refrain from using arbitrary detention under any circumstances," Markus Ederer said in a statement.
US State Department spokesman Mark Toner, meanwhile, said Monday that Ai's detention was "inconsistent with the fundamental freedom and human rights of all Chinese citizens."
"We urge the Chinese government to release him immediately," he added. Germany, France, Britain and Austria have also expressed concern about Ai, known for helping design Beijing's famous "Bird's Nest" Olympic stadium.
Rights groups said Ai's detention marked a widening of China's crackdown on dissent, with Paris-based media watchdog Reporters Without Borders warning that the Chinese government was "trying to silence all of its critics."
No stranger to Chinese authorities
Ai, a burly, goateed man whose work is currently on display in London's Tate Modern gallery, has repeatedly challenged Chinese authorities.
He has investigated school collapses in the huge 2008 earthquake in the southwestern province of Sichuan, and more recently launched a "citizen's investigation" into a Shanghai fire that killed at least 58 people in November.
At the 2009 trial in Sichuan of activist Tan Zuoren, who also probed school collapses and was later handed a five-year jail term, Ai said he was detained and beaten by police who blocked him from testifying on Tan's behalf.
In February this year, he said his first large solo exhibition in mainland China was cancelled after organisers said the timing was too politically sensitive.
A month earlier, his newly built Shanghai studio was demolished in apparent retaliation for his criticism of city policies, and he was blocked from leaving China in December ahead of the Nobel Peace Prize ceremony in Oslo.
Just last week, Ai told AFP he planned to set up a studio in Germany to showcase his work after facing huge hurdles in exhibiting art in his home country.
"It's very discouraging what's happening here and if I want to continue to develop my work, I have to find a base," he said, adding he still wanted to live in Beijing " unless the situation is an absolute threat to my life."
