BEIJING - Police have captured more suspected terrorists linked to an attack on April 23 in northwest China's Xinjiang Uygur autonomous region, Vice Minister of Public Security Meng Hongwei said on Monday.

Meng did not disclose the number of suspects seized, but said the police have made major progress in the investigation.

Police have tracked down a batch of homemade explosives, lethal weapons, and flags of "East Turkistan" terrorists, according to Meng.

The violent clash happened last Tuesday in a town of Bachu County, Kashgar Prefecture, some 1,200 km southwest of Urumqi, regional capital of Xinjiang.

The clash between the terrorists and authorities left 21 people dead, including 15 community workers and police officers and six terrorists, local authorities said. Eight terrorist suspects were captured on Tuesday.

The clash is a "serious violent terrorist criminal case," which led to significant losses, Meng said.

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, innocent residents, disregarding their gender or ethnic group. The tragedy "fully showed their anti-human and anti-social nature," he 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, Meng said.

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