Police shot dead six people and six more died when explosives they were carrying detonated in Xinhe county, according to weekend media reports. Blasts struck a beauty salon and a vegetable market.
Yu Zhengsheng, a member of the Communist Party's seven-man Politburo Standing Committee, called for action to ensure that religious practice did not spill over into illegal acts.
His remarks, quoted by the official People's Daily, made no direct reference to Xinjiang. But China has long objected to unauthorised activities associated with religious practice by Xinjiang's large Muslim minority as well as other groups, like Buddhists in restive Tibet and various underground churches.
"Religious followers must expand consciousness of the state, the law and citizenship within religious circles so that the faithful naturally conduct religious activities within the bounds of law and policy," he said.
The official Xinhua news agency quoted police in Xinjiang as saying a man identified as Ibrahim Qahar had organised a group of 17 people to produce the explosives at a rented house.
It said police had seized devices, but gave no details on their nature.
"A man named Ibrahim Qahar had organised illegal religious activities and spread religious extremism since May last year," Xinhua said.
Five suspects were captured and one policeman was slightly wounded in the incident after the group rode three motorcycles to set up the blasts on Friday evening, Xinhua said.
A spokesman for the main Uighur exile group, the World Uyghur Congress, had suggested at the weekend that the beauty salon was a front for a brothel that had offended Uighurs' "traditional lifestyles".
Xinjiang has been the theatre of numerous incidents of unrest in recent years, which the government often blames on the separatist East Turkestan Islamic Movement (ETIM), although experts and rights groups cast doubt on its existence as a cohesive group. Authorities blamed Uighur extremists for a suicide attack last year in Beijing's Tienanmen Square.
Muslims in the region, who speak a Turkic language, chafe at restrictions they say authorities impose on their culture. The region lies on the borders of ex-Soviet Central Asia, India and Pakistan.
Around 100 people, including several policemen, have been killed in violence since last April, according to state media reports. In 2009, nearly 200 people were killed in the Xinjiang capital, Urumqi, in rioting between Uighurs and Han Chinese.