Police in China's western Xinjiang region say they have fatally shot two men who participated in a killing spree that is being blamed on Pakistani-trained terrorists.

Police say the men were found hiding in a cornfield outside the city of Kashgar, where attackers killed six people and wounded 15 others on Sunday. With their deaths late Monday, police say they have killed or captured all those involved in the attack.

Sunday's killings capped a weekend of violence that claimed at least 20 lives in the Silk Road city located near China's borders with Kyrgyzstan and Uzbekistan. Authorities say the leaders of the latest attack were trained at camps in Pakistan run by the East Turkestan Islamic Movement, an extremist group seeking independence for the ethnic Uighur population of Xinjiang.

In Washington, a spokesman for the Uyghur American Association expressed regret at the loss of lives but said many Uighurs have been pushed to “extreme desperation” by a “relentless atmosphere of fear and hopelessness.”

The organization said China's government must take responsibility for creating that climate of fear and take steps to end its brutality against Uighurs.

Pakistan's Foreign Ministry pledged cooperation with China in combating the East Turkestan Islamic Movement, which is listed by the United States and other countries as a terrorist organization.

The violence in Kashgar began Saturday, when two men hijacked a truck, killed its driver and then rammed the truck into a crowd. Authorities say the men jumped out, hacking at passers-by randomly, leaving eight dead. Police killed one of the attackers.

On Sunday, a group of men overran a restaurant, killing the owner and a waiter before setting the building on fire. Police say they then ran into the street, hacking at passers-by and killing four more. Police say they killed five of the men and captured others. Two escaped and were killed in the cornfield late Monday.

Chinese state media report a strong presence by security forces in cities across Xinjiang since the attacks.

Tensions have been high in the region since 2009, when ethnic riots involving Uighurs and Han Chinese killed about 200 people.

Uighurs are a Turkic-speaking, mainly Muslim group with close ethnic links to the peoples of Central Asia.