A six-year prison sentence reportedly given to a man in China's mainly Muslim Xinjiang region for growing a beard was "absurd", an overseas group said Monday as accounts of the penalty disappeared online.

Dilxat Raxit, a spokesman for the exile World Uyghur Congress, said the case was "typical of the political persecution" faced by Uighurs, the mostly Muslim, Turkic-speaking minority group that calls Xinjiang home.

"This is a case that would not happen in any other country in the world," Raxit said in a statement. "It is unacceptable and absurd. It exposes China's hostile attitude and crisis of governance."

He added: "If a Chinese person grows a beard, it is a personal fashion he is allowed to choose freely. If a Uighur grows a beard, he is a religious extremist.

"China's goal is to use judicial means to force Uighurs to accept Chinese people's traditions and give up their own way of life."

On Sunday the China Youth Daily reported that a court in Xinjiang's desert oasis city of Kashgar sentenced a 38-year-old Uighur man to six years in jail for growing a beard, while his wife was given two years for veiling herself.

The man "had started growing his beard in 2010" and his wife "wore a veil hiding her face and a burqa", the paper said. Both practices are discouraged by local authorities.

The couple were found guilty of "picking quarrels and provoking trouble", a vague accusation regularly used in the Chinese judicial system.

An employee of Kashgar's propaganda department declined to confirm the report on Monday, telling AFP: "I know nothing about this."

For more than a year the authorities in Xinjiang have been campaigning against men growing beards -- a practice officials associate with extremist ideas.

A campaign dubbed "Project Beauty" also encourages women to leave their heads bare and abandon wearing the veil, which some Muslims see as a religious requirement.

Rights groups believe Beijing's repression of Uighur culture and religion has fanned tensions in Xinjiang, a resource-rich region that abuts central Asia.

- 'Simple and crude' -

Violence increased last year and at least 200 people were killed in a series of bombings and deadly clashes with security forces, blamed by Beijing on "separatists" and "religious extremists".

Beijing defends its policies, arguing it has boosted economic development in the area and that it upholds minority and religious rights in a country with 55 recognised ethnic minorities as well as the Han majority.

Foreign ministry spokeswoman Hua Chunying told reporters: "The Chinese government will do its best to promote stability and economic development as well as harmonious coexistence of all ethnic groups in Xinjiang."

By Monday the China Youth Daily report and several other articles on the case had been deleted from mainland news sites.

But the initial accounts incited debate among users of China's popular online social networks. Some said the punishment was an appropriate way to guard against extremism.

"Anyone dressed that way is a terrorist, not a Muslim!" wrote one user on Sina Weibo, a Chinese equivalent of Twitter.

Others dismissed the anti-beard campaign as a "simple and crude" measure that would do little to ensure public safety.

Some referred to the spectacularly hirsute German political theorist whose writings are a cornerstone of Communist Party ideology to this day, with one asking: "How many years would Marx have been sentenced to?"