Calm has returned to Kashgar in the Xinjiang Uygur autonomous region following a deadly terror attack that left 21 dead.

The clash, described by the region's information office as a "severe, violent, terror incident", happened after three community workers in Selibuya township, Bachu county, found several suspicious people and knives in a house on Tuesday.

They reported the details to their supervisor but were then restrained by suspected terrorists, according to the Xinjiang government's information office.

When police and community workers arrived, they were ambushed by attackers inside and outside the house. The attackers, who had killed the three community workers that had been held captive, then set fire to the house.

By the time police brought the situation under control, 15 people had been killed by the gang. Six gang members were shot dead at the scene, bringing the death toll to 21, the information office said on Wednesday.

Of the dead, including police, community workers and gang members,10 are from the Uygur ethnic group.

The initial investigation showed that the group was planning terror attacks, the information office said.

Mutalif Wubuli, commissioner of Kashgar prefecture, told China Daily the violent attack was properly dealt with and public order in Selibuya has been restored, and eight suspects have been arrested.

"People's lives are back to normal in Selibuya, and the arrested suspects are being questioned by police," the commissioner said.

Qi Baowen, commander of the Xinjiang Armed Police, said consequences of the incident are relatively severe because there are many casualties.

In March, courts in Kashgar sentenced 19 people for their involvement in organized terror activities and for spreading extreme religious information via Internet and cellphones.

The region has been on the front line of battling separatists, extremists and terrorists. The July 5, 2009, riot in Urumqi, capital of Xinjiang, left 197 dead.

Social management in communities is the foundation of maintaining stability in the region, Xiong Xuanguo, secretary of the Political and Legal Affairs Commission of Xinjiang, said during a conference in March.

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