URUMQI - Police opened fire and killed seven kidnappers during a hostage rescue mission in Northwest China's Xinjiang Uygur autonomous region Wednesday night, local authorities said Thursday.

A group of "violent terrorists" kidnapped two people in the remote mountainous areas of Pishan county, Hotan prefecture, at about 11 pm Wednesday. Police opened fire as the kidnappers "resisted arrest," a spokesman with the Xinjiang regional government said.

Seven kidnappers were shot dead, and four others were wounded and arrested. One police officer was killed and another wounded in the rescue. Two hostages were freed.

No more details were immediately available as authorities are investigating the case.

But there was speculation that the kidnapping was linked to a surge in religious extremism in the Muslim ethnic Uygur-dominated area that borders the Kashmir region controlled by Pakistan and India.

Police reported another kidnapping earlier this month in Pishan in which the extremists kidnapped and brutally murdered a Uygur man for drinking alcohol, an act considered taboo by Muslims.

"Salute the police officer who sacrificed his life for the people," a microblogger wrote on Sina Weibo, China's most popular Twitter-like service.

"There should be zero tolerance toward violence and terrorism," wrote another microblogger. "The government must high-handedly crack down upon violent elements, otherwise the government is delinquent."

Pishan, like many towns and villages in the south of Xinjiang, is predominantly populated by Uygurs, and the Han people, China's majority ethnicity, account for less than 2 percent of the local population.

The region is no stranger to violence. In the nearby city of Hotan in July, a mob stormed a police station, hurled burning gasoline cylinders into rooms, took hostages, and attacked people indiscriminately with axes and knives. Eighteen people, including 14 attackers, were killed in the clash with police forces.

Days after the violence, two separate public attacks occurred in the city of Kashgar, another city in the south of Xinjiang, leaving 13 people dead and 44 others injured. Authorities said overseas-trained terrorists were responsible for the attacks.

Four suspects involved in the Hotan and Kashgar attacks were sentenced to death by court in September.

Uygurs traditionally practice a moderate form of Islam. But security experts said recent violence shows that marks of religious extremism are on the rise. The trend, if unchecked, could lead to more bloodshed as extremists are becoming bolder, and their attacks more brutal, they warned.

Store-owners and vendors in some rural areas of Pishan said they are afraid to sell alcoholic drinks or cigarettes over fears of retaliation. A local resident told Xinhua that the lifestyle of local Uygurs "had been seriously affected" by the rise of an extremist atmosphere in recent years.

Xinjiang's top official, Zhang Chunxian, has ordered a harsh crackdown on religious extremists in the government's clampdown on terrorism.

Zhang, secretary of the Xinjiang regional committee of the Communist Party of China (CPC), ordered local officials to rely on the public's help in curbing illegal religious activities and to crack down on the use of religion to incite violence or organize terrorist attacks.

He said the managing of religious affairs should follow the central government's policy of "protecting the legitimate, banning the illegal, fighting infiltration and cracking down on crimes."