Foreign ministry insists security authorities acting lawfully as family claim 'economic' investigation is politically motivated
China's foreign ministry has insisted that a police investigation into artist Ai Weiwei has "nothing to do with human rights or freedom of expression" after an international outcry against his detention.
Relatives say official claims that the 53-year-old is being investigated for "economic crimes" are absurd, claiming the accusations are politically motivated because of his record of activism and social criticism.
Foreign ministry spokesman Hong Lei told a regular news conference that it was his "understanding that the public security authorities are investigating Ai Weiwei according to law on suspicion of economic crimes".
State news agency Xinhua had previously published a one-line report announcing the probe, only to delete it within the hour.
Asked about criticism by western governments, Hong added: "China is a country ruled by law and will act according to law. We hope that the countries concerned will respect China's decision.
"This has nothing to do with human rights or freedom of expression."
Chinese law states that police must inform an individual's relatives or place of work within 24 hours of detention, unless there is no way to do so or it would "impede the investigation".
His family say they have yet to be informed. In a letter to police, Ai's wife Lu Qing demanded to know her husband's whereabouts and condition and why he was being held.
"As of 8am today [Thursday], it has been 96 hours since Ai Weiwei was taken away from Beijing airport, and I haven't heard a single word about him," she wrote.
The police have not answered media queries about the artist, who has been missing since Sunday, or his friend Wen Tao, 38, who was also reportedly detained that afternoon.
"The economic crimes report is absurd, because the way he was taken and then disappeared shows it's nothing of the sort," Ai's older sister, Gao Ge, told Reuters.
"This is more like a crime gang's behaviour than a country with laws."
She said the artist had previously told relatives he might one day be jailed for his activities. "He was very clear that we shouldn't try to meddle and stop him speaking out … My mother cried," she said.
Ai's mother, Gao Ying, said the "economic crimes" allegations were being used to stifle his activism, adding: "If he's not released, this will be the start of a long struggle."
She said her son was unlikely to accept charges to win a swift release.
"If he's not given justice, he'll refuse to come out, I think. That's his character," she said.
Human rights groups say similar accusations of financial wrongdoing – such as tax-related charges – have been used to intimidate activists in the past.
In an interview last year, Ai told the Guardian that he recognised the state might take action against him and said security officials had visited his bank.
But he added: "I also have to speak out for people around me who are afraid, who think it is not worth it or who have totally given up hope. So I want to set an example: you can do it and this is OK."
Liu Xiaoyuan, a lawyer who has worked with Ai, said that "economic crimes" was a wide-ranging description and it was not clear what the actual accusations were.
Ai's detention comes amid a crackdown that has seen scores of activists, dissidents and lawyers criminally detained, formally arrested or simply disappear.
Twitter users reported that police detained human rights lawyer Ni Yulan and her husband Dong Jiqin on Wednesday and a contact of the couple confirmed they had been taken.
Ni was disbarred after helping residents who were being evicted, and is disabled as a result of being badly beaten after filming a forced demolition. Her own house was bulldozed and she was jailed for interfering with public administration.
On her release, the couple were blocked from renting a flat or staying with friends. For several weeks last year they lived in a tent in a park. As attention to their case grew, police moved the couple to a hotel, but authorities cut off their power and water several months ago.
Police did not respond to faxed queries about the couple. A receptionist at the Yuxingong hotel said he did not know about the situation.