Chinese artist Ai Weiwei 'faces $1.9m in tax and fines'
China's authorities are demanding that artist Ai Weiwei pay more than 12m yuan ($1.9m, £1.2m) in unpaid taxes and fines, one of his friends says.
Mr Ai is one of China's leading artists, and the most prominent figure caught up in a recent crackdown on critics of the Communist Party.
He was released last week after being detained at a secret detention centre for 80 days.
His family has insisted he is being targeted for his political activism.
Beijing's Tax Bureau claims Ai Weiwei owes 4.85m yuan in unpaid taxes, and insists he must pay an additional fine of 7.3m.
Liu Xiaoyuan, a lawyer and close friend of the artist, says he saw the letter with the demand after it was delivered on Monday. Mr Ai must respond within three days, he added.
There was an international outcry when police seized Ai Weiwei and held him incommunicado.
The authorities released him last week, saying he had admitted tax evasion.
The terms of Ai Weiwei's bail prevent him from speaking out publicly, so it has been left to his family to deny that he evaded tax.
They say the tax demand covers the past 10 years, according to reports.
They want to know why the issues are being raised only now, and insist the company involved in the tax affair is not controlled by Mr Ai, but his wife.
His mother believes the artist is being persecuted, because the authorities want to silence him and stop his political activism.
In recent weeks more than 100 other prominent activists, human rights lawyers, and internet bloggers have been targeted in a crackdown launched by China's communist leaders.
Human rights groups say it is the most grave silencing of voices of dissent in China since the Tiananmen massacre more than 20 years ago.
The trigger for the crackdown appeared to be anonymous calls on the internet for Chinese people to stage a popular revolution for democracy, like those sweeping North Africa and the Middle East.
A number of others, detained at the same time as Ai Weiwei, have also been freed. They include Mr Ai's driver, accountant, assistant and a designer.
Last Sunday the human rights activist Hu Jia, imprisoned for three and a half years, was released too.
In the past Ai Weiwei has exhibited his work in London, New York and Berlin. He designed the Bird's Nest stadium for the 2008 Beijing Olympics.
But he also became an outspoken critic on a number of national scandals, including the deaths of students in shoddily built schools in the 2008 Sichuan earthquake, and the harm done to children by tainted infant formula.