Much of the unrest, they argue, is due to frustration at controls over the culture and religion of the Uighur people who live in Xinjiang, a charge Beijing denies.
Chinese security forces in the far western region of Xinjiang killed 28 "terrorists" from a group that carried out a deadly attack at a coal mine in September under the direction of "foreign extremists", the regional government said on Friday.
The news carried by the official Xinjiang Daily was the first official mention of the Sept. 18 attack at the Sogan colliery in Aksu, in which it said 16 people, including 5 police officers were killed, and another 18 people injured.
Radio Free Asia, which first reported the incident about two months ago, said at least 50 people had died.
Attackers fled into the mountains and authorities launched a manhunt with more than 10,000 people participating every day, forming an "inescapable dragnet", the Xinjiang Daily said.
"After 56 days of continuous fighting, Xinjiang destroyed a violent terrorist gang directly under the command of a foreign extremist group. Aside from one person who surrendered, 28 thugs were completely annihilated," the newspaper said.
China's government says it faces a serious threat from Islamist militants and separatists in energy-rich Xinjiang, on the border of central Asia, where hundreds have died in violence in recent years.
Rights groups say China has never presented convincing evidence of the existence of a cohesive militant group fighting the government. Much of the unrest, they argue, is due to frustration at controls over the culture and religion of the Uighur people who live in Xinjiang, a charge Beijing denies.
The Xinjiang Daily said two people who appeared to have Uighur names were leaders of the unnamed foreign group.
Beginning in 2008, the Xinjiang group's members began watching extremist videos and communicated six times with an extremist group outside of China's borders, requesting tactical guidance, the paper said.
"Members of this foreign extremist group transmitted orders to the gang many times and demanded pledges of loyalty," it said, without elaborating.
It is unclear why the government had not disclosed the incident earlier. Some previous other attacks have also not been reported until days or even weeks after they happened.
Calls to the Xinjiang government seeking comment went unanswered.
China's Foreign Ministry, generally the only government department to regularly answer questions from foreign reporters, referred questions on the case to the Xinjiang government.
"China must continue to fight against this kind of terrorist attack with determination, to protect the lives of the people, protect the stability and safety of society," ministry spokesman Hong Lei told a daily news briefing.
Pictures carried on the Xinjiang government's news website showed armed security forces crossing rivers and clambering up rocks in what looked like a remote part of the region.
It also showed civilians with sticks fanning out across scrubland helping to look for the suspects.
Western nations have been reluctant to cooperate in China's anti-terrorism campaign in Xinjiang, nervous about being implicated in possible human rights abuses, accusations China denies.
Since last week's attacks in Paris, Chinese state media has lambasted Western countries for their "double standards" on terrorism.
China says that it too is threatened by groups like Islamic State, which announced this week it had killed a Chinese hostage.
Chinese officials also say some Uighurs have gone to fight with radical groups in the Middle East.