BEIJING (AP) — China claimed Tuesday that a clash between police and locals in a restive far western region was an organized and premeditated attack by a small terrorist group.

The official Xinhua News Agency said that 16 people were killed in the Sunday night incident — 14 assailants and two police officers — in China’s northwestern region of Xinjiang, home to a simmering rebellion against Chinese rule among parts of the Muslim Uighur population who want more autonomy from Beijing. Recent clashes, including an attack on a police station, left dozens of people dead this year.

The Chinese government typically calls such incidents terrorist attacks linked to radicals based overseas, although there is little evidence that they are carefully organized. In many cases, the violence appears caused by anger over poverty and strict rules on Uighur culture and Muslim worship.

Xinhua described the assailants as “terrorists” and said an initial investigation found that they were from a 20-member terrorist group led by a man identified as Hasan Ismail. Tuesday’s report said six members of the group were captured, but it did not say if Ismail was among those killed or apprehended.

Police had been searching for Ismail in a village in Shufu county in far-west Kashgar prefecture came under attack with explosive devices and firearms at around 11 p.m., Xinhua said.

Calls to local authorities rang unanswered or were picked up by officials who said they did not know about the attack.

Sweden-based Uighur (pronounced WEE’-gur) activist Dilxat Raxit said Sunday’s incident was the latest example of how Chinese security forces are increasingly opting to kill suspects at the scene rather than capturing them and putting them on trial. Police also killed nine assailants in the attack on the police station in November.

“They are now opening fire and killing people, then calling them terrorists,” Raxit said by phone. “This deprives them of their right to defend themselves in a court.”