China's Foreign Ministry removed all references to a detained artist from its official transcript of a news conference given by its spokesman, in an apparent sign it wants to stifle discussion of the case.
Ten of the 18 questions asked at the news conference Thursday concerned Ai Weiwei, a prominent artist and activist who was detained Sunday at Beijing's international airport along with an assistant, Wen Tao. All 10 questions were omitted from the transcript posted Friday on the Foreign Ministry's website.
The ministry did not immediately respond to requests for an explanation.
Ai is the most prominent target so far in China's massive crackdown on dozens of lawyers, writers and activists following online calls for protests similar to those in the Middle East and North Africa. No protests have occurred here.
Spokesman Hong Lei had told the regularly scheduled news conference that Ai was being investigated for economic crimes, but he gave no details. He said the case had nothing to do with freedom of expression, although Ai has often been a target of government harassment.
"China is a country under the rule of law, and relevant authorities will work according to law," Hong said.
Foreign governments and international rights groups have called for Ai's release, saying the authorities appeared to be punishing him for his activism.
Chinese authorities sometimes try to silence critics by accusing them of tax violations or other nonpolitical crimes. Beijing police have refused to comment on Ai's case.
Police have expanded their investigation in the days since Ai's detention, calling in friends, family members and associates for questioning. Officers returned to Ai's studio on Friday, demanding to see his accounting ledgers, according to assistants who were present at the time.
Ai is among China's best-known artists internationally and recently exhibited at the Tate Modern gallery in London. His activism has included leading a campaign for an independent investigation into the deaths of thousands of children whose badly built schools collapsed in the massive 2008 Sichuan earthquake, an issue the government has sought to hush-up.
China's media have been largely silent on Ai's case, although the outspoken Global Times newspaper published by the Communist Party mouthpiece People's Daily has run editorials on two consecutive days accusing the West of using his case to denigrate China's legal system.
In its editorial Friday, it appeared to suggest that the case against Ai wasn't entirely open and shut.
"Just because Ai Weiwei is being investigated by police on suspicion of committing economic crimes doesn't necessarily mean he will be convicted. However, guilty or not is for the court to say and foreign diplomatic and public opinion pressure will not be the determining factor," the newspaper said.
Associated Press writer Isolda Morillo contributed to this report.