Chinese crackdown on Uighur Muslim, continues in the country's restive Muslim-majority Xinjiang province, as security agencies arrested over 139 activists over the past few weeks on charges of promoting jihad online.

Xinjiang is a Muslim majority province, home to the Uighur ethnic minorities, several of whom resent Chinese authority and repression of their religion and culture. Extremist groups in the region have been carrying out alleged terror attacks campaigning for a separate Muslim state.

Following China's request, Pakistan has recently banned three of these Islamic outfits whom China blames for inciting local population and carrying out extremist activities. The banned outfits include East Turkestan Islamic Movement (ETIM), Islamic Movement of Uzbekistan (IMU) and Islamic Jihad Union (IJU).

"Those Uighurs who were detained were expressing online their dissatisfaction at China's dominance of their localities and systematic repression," Dilxat Raxit, a spokesman for the exiled World Uyghur Congress, is reported to have told Reuters news agency.

Reports in the China Daily, quoting an anonymous source said the arrested activists were: "spreading religious extremism including jihad."

"Our local public security bureaus are strongly cracking down on those who engage in illegal activities online," another Chinese newspaper, the Xinjiang Daily newspaper reported.

"Xinijang must not allow the internet to become a platform for crime."

Police in Xinjiang have "handled an increasing number of cases in which individuals have posted or searched for religious extremist content on the Internet", the Daily added.

Uighur Muslims are a Turkish-speaking minority of eight million in the northwestern Xinjiang region.

Xinjiang, which activists call East Turkestan, has been autonomous since 1955 but continues to be the subject of massive security crackdowns by Chinese authorities. Rights groups accuse Chinese authorities of religious repression against Uighur Muslims in Xinjiang in the name of counter terrorism.

Analysts say the policy of transferring Han Chinese to Xinjiang to consolidate Beijing's authority has increased the proportion of Han in the region from five percent in the 1940s to more than 40 percent now.