"They had close connections to Al Qaeda," Shi said at a news conference during China's annual legislative session.
"There terrorists were trained by the Taliban in Afghanistan and sent to China by them," Shi said, adding that more than 1,500 semi-assembled grenades were seized in the raid east of China's border with Kyrgyzstan.
"They were trained overseas and sent to China by overseas terror organizations to engage in disruptive activities," Shi said, without giving specific details about the alleged links or what their goal had been.
China has said before that ETIM has links to Al Qaeda, and labels the group a terrorist organization, as does the United States.
China has long said that militants among the region's dominant ethnic Uighurs are leading a violent Islamic separatist movement in Xinjiang. The Uighurs are Turkic-speaking Muslims with a language and culture distinct from the majority of Chinese.
Critics accuse Beijing of using claims of terrorism as an excuse to crack down on peaceful pro-independence sentiment and expressions of Uighur identity.
About two dozen Uighurs were captured by U.S. forces in Afghanistan following the attacks of Sept. 11, 2001.
China has demanded their return, but the United States fears they might face persecution there. Five Uighurs were sent to Albania last year after no other country would accept them.
Ismail Tiliwaldi, chairman of the Xinjiang Uighur region, told the same news conference that the government is making efforts to improve the situation in the area by accelerating economic and social development.
"Xinjiang enjoys social stability and there is little room for activities of the East Turkestan terrorist forces because we now have more good guys and fewer bad guys," he said.