China has imprisoned almost two dozen people - mostly Muslim religious leaders - in the western region of Xinjiang, in a stepped up crackdown on "illegal religious activities", Chinese media reported.

The 22 suspects, including so-called "wild imams", were given prison terms ranging from five to 16 years at a mass public sentencing in Xinjiang on Monday, the state-run China News Service reported.

Among religious leaders imprisoned were those who continued "religious activities", including preaching, after being sacked from their official posts, it said.

Others were accused of inciting hatred against the country's predominant ethnic Han Chinese, using supersitution to destroy the law, and picking quarrels and provoking trouble, it said.

Xinjiang is home to the mostly Muslim minority group known as the Uighurs.

China has vowed to crack down on religious extremism, which it blames for a string of violent attacks this year in Xinjiang and elsewhere.

'No rights to faith'

However, exiles and activists say Chinese controls on the religion and culture of the Uighur people is more of a cause of violence than armed groups.

The exiled World Uighur Congress condemned the mass sentencing in a statement, saying it was religious repression that trampled the rights of their people.

"The so-called distinction between legal and illegal religion is determined based on China's political needs," said Dilxat Raxit, a spokesman for the group.

"Uighurs basically have no rights to faith."

Mass public sentencings have become common in Xinjiang, with state television often showing them taking place in packed outdoor auditoriums. Rights groups have said mass trials and sentencings deny the accused the right to due process.

A court in September jailed for life the country's most prominent advocate for Uighur rights in a case that provoked an outcry in the West and among rights groups.

China is worried that state enemies in Xinjiang can get support from Islamists in nearby Pakistan and Afghanistan.