Xinjiang has come under increasingly pervasive security in recent years, especially since July 2009, when the regional capital, Urumqi, suffered the worst ethnic violence in China in many years as Uighurs attacked Han Chinese residents after a protest by Uighurs that was broken up by the police then spiraled into bloodshed. At least 197 people were killed, most of them Han, according to the Chinese government, and Uighur neighborhoods became the target of violent demonstrations and trashing by Han Chinese, as well as sweeping arrests by the police.

Since then, Xinjiang has experienced sporadic flare-ups of protest and violence. But advocates of Uighur self-rule and human rights groups say the Chinese government has exaggerated the level of organization behind these incidents in an effort to discredit legitimate Uighur grievances.

In Beijing this month, Zhang Chunxian, the Communist Party head of Xinjiang, told reporters at the annual meeting of the national Parliament that “although the situation remains tough, the overall stability in Xinjiang is improving and under control.”

The latest report said that some of the people convicted in Kashgar, in southwestern Xinjiang, used cellphones and videos to spread the militant ideas of the East Turkestan Islamic Movement and Islamic Movement of Uzbekistan — two groups accused by China and its Central Asian neighbors of fomenting separatism. Parts of Xinjiang border Pakistan, and a small and isolated patch adjoins Afghanistan.

In one case in Kashgar, eight people formed a group that “organized training in terrorist capabilities, bought weapons, and planned to assassinate local law enforcement officers and police,” engaged in illegal religious proselytizing, and collected money to send supporters abroad, the report said. It did not say how far advanced the plots were, or which country the followers intended to travel to. Two of the accused ringleaders were sentenced to life in prison.

In another case in Kashgar, three people were accused of forming a group that committed similar crimes, and of beating people and smashing vehicles. The court in Bayingol, in northern Xinjiang, convicted one person of setting up an Internet chat room to “promote ethnic separatism, terrorist violence and religious extremism.”

Several government offices contacted in Xinjiang could not give the Uighur rendering of the names of the accused or other details, and nor did the offices or the report say whether they pleaded innocent or guilty or intended to appeal the sentences.

China’s party-run courts rarely find in favor of defendants, especially in politically sensitive cases.