KASHGAR, Xinjiang - Eleven runaway suspected terrorists linked to a deadly attack on April 23 in northwest China's Xinjiang Uygur autonomous region have been captured, local police sources said on Monday.

Police said that as of Sunday, they had nabbed all 19 suspects from the region's Kashgar Prefecture, the Mongolian Autonomous Prefecture of Bayingolin and the regional capital of Urumqi.

The announcement came six days after a violent clash between the terrorists and authorities in a town at Kashgar's Bachu County, some 1,200 km southwest of Urumqi, leaving 21 people dead.

The fatalities included 15 community workers and police officers and six terrorists, local authorities said after the attack.

Eight terrorist suspects were captured on the day of the clash, they added.

According to the Xinjiang police, the terrorist group, headed by Qasim Muhammat, was founded in September 2012.

The group members regularly watched video clips advocating religious extremism and terrorism and attended illegal preaching ceremonies.

Since early December 2012, they had always gathered at the house of Muhanmetemin Barat, a group member, to do physical training and to practise killing skills they had learned from the terrorist video clips, the police said.

In early March this year, the ring made explosive devices and remote controllers and later carried out five explosion testing.

They had planned to "do something big" in the densely populated public areas in Kashgar in the summer, the police said.

The group members were spotted making explosives on April 23 by local police and community workers, which led to the deadly clash.

Vice Minister of Public Security Meng Hongwei said on Monday that police have tracked down a batch of homemade explosives, lethal weapons, and flags of "East Turkistan" terrorists after the April 23 clash.

He called the clash "a serious violent terrorist criminal case, " which led to significant losses.

Meng warned of the "prolonged and complicated" nature of the anti-terror fight in Xinjiang at present. He said sometimes the fight can be "relatively intense," with the incessant incitement and influence from overseas "East Turkistan" secessionist terrorists.

During the clash, the terrorist suspects brutally killed law enforcement personnel and innocent residents, disregarding their gender or ethnic group.

The tragedy "fully showed their anti-human and anti-social nature," Meng said.

The "three evil forces" of separatism, extremism and terrorism, which could do great harm to Xinjiang's prosperity and stability, are the common enemies of the people of all ethnic groups in Xinjiang, he said.

The official vowed an iron-handed crackdown against terrorism, saying the police will use every possible means to find and punish terrorists with no mercy.

Also on Monday, the 15 community workers and police officers who died during the attack were honored for their bravery and sacrifice.

A commendation meeting was held in the morning with the regional committee of the Communist Party of China (CPC) and government posthumously awarding them each as a "regional anti-terrorist hero," according to the regional government.

Ten of the 15 were of the Uygur ethnic group. Three were of the Han ethnic group. The remaining two were of the Mongolian ethnic group.

Seven of the 15 were also posthumously honored as a "regional outstanding CPC member".

Nur Bekri, the regional governor, said at the meeting that the nature of the terrorist clash was not about ethnic or religious issues, but a terrorist act to split the motherland and undermine national unity.

"It is a political fight between separatism and anti-separatism, and between safeguarding the national unity and undermining the national unity," he said. "We will leave no room for compromises and concessions."