The head of China's largest mosque was murdered after conducting morning prayers, the local government in far western Xinjiang said Thursday, amid intensifying violence in the turbulent region.

Jume Tahir, the government-appointed imam of the 600-year-old Id Kah mosque in the city of Kashgar, was killed Wednesday by "three thugs influenced by religious extremist ideology", the Xinjiang government web portal Tianshan said.

Police launched an all-out investigation and shot dead two of the alleged assailants while capturing the other at about noon on Wednesday as they violently resisted with "knives and hatchets," Tianshan said.

Tianshan said Tahir's killing was "premeditated" and that the suspects intended to commit a "ruthless murder".

It also said they wanted to "increase their influence through 'doing something big'".

Tianshan identified the suspects by their names in phonetic Chinese. The official Xinhua news agency in an English-language report gave their names as Turghun Tursun, Memetjan Remutillan and Nurmemet Abidilimit.

Neither Tianshan nor Xinhua initially identified who among them was shot dead and who was apprehended.

Tahir was found dead in a pool of blood outside the mosque's prayer house, Radio Free Asia (RFA) reported earlier on its website.

Xinjiang, home to China's mostly Muslim Uighur ethnic minority, has seen escalating violence which in the past year has spilled over into other parts of China.

RFA cited what it described as "witnesses and other officials", including the director of a neighbourhood stability committee in Kashgar, who described the killing as an assassination.

Imams and other religious leaders in China are appointed by the government and subject to strict control on the content of their preaching.

- 'Critical' of Uighur violence -

US-based RFA said that Tahir had been critical of violence carried out by Uighurs, and China's official Xinhua news agency in early July quoted him as condemning terrorist violence carried out in the name of ethnicity and religion.

Tahir, 74, "enjoyed a high reputation among Muslims nationwide", Xinhua said in its dispatch Thursday.

Dilxat Raxit, spokesman for the exiled World Uyghur Congress (WUC), did not condemn the killing.

"Chinese policies in the area have caused things to happen which should not happen," he told AFP in an email.

"According to local Uighurs, Jume Tahir consistently co-operated with the government, aided the monitoring of religious activities, and used his position in the mosque to promote Chinese policies which are unacceptable to Uighurs," he said.

"Local Uighurs suspected he had a special relationship with the Chinese ministry of security."

The Id Kah mosque is said to have a capacity of up to 20,000 people.

Kashgar, where the mosque is located, is an old oasis city that was part of the Silk Road trade route that ran from Europe to Asia.

The killing of Tahir came two days after dozens of people died in violence between Uighurs and security authorities in the Kashgar region.

Nearly 100 people were left dead or wounded, the WUC said, while authorities put the toll in the "several tens" in what they called a "terror attack" on a police station and township in Shache county, known as Yarkand in the Uighur language.

- Series of attacks -

Beijing commonly blames separatists from Xinjiang for carrying out terror attacks which have grown in scale over the past year and spread outside the restive and resource-rich region.

A market attack in Urumqi, Xinjiang's capital city, in May left 39 people dead, while a deadly rampage by knife-wielding assailants at a train station in Kunming in China's southwest in March killed 29 people.

They came after a fiery vehicle crash at Tiananmen Square, Beijing's symbolic heart, in October last year.

The violence has led China to carry out a broad crackdown on terrorism. President Xi Jinping on a visit to Xinjiang in late April called for a "strike first" strategy to fight terrorism and said the Kashgar area is China's "front line in anti-terrorist efforts".

Chinese prosecutors on Wednesday brought charges of separatism -- which can carry the death penalty -- against prominent Uighur academic Ilham Tohti, detained earlier this year.

Rights groups and analysts accuse China's government of cultural and religious repression which they say fuels unrest in Xinjiang, which borders Central Asia.

The government, however, argues it has boosted economic development in the area and that it upholds minority rights in a country with 56 recognised ethnic groups.