Beijing ? China issued a “Most Wanted” list of 21 rioters Friday – shown in grainy photos waving knives and fighting during last week’s violence over Chinese rule in Tibet. Thousands of troops continued to push into western China to contain unrest.

U.S. House Speaker Nancy Pelosi gave support to the Tibetan cause on a visit to the Dalai Lama, calling China’s crackdown “a challenge to the conscience of the world.”

Her criticism added to a chorus of international concern over Beijing’s harsh response to the anti-government protests, as China sought to blame supporters of the Tibetan spiritual leader for unrest.

“If freedom-loving people throughout the world do not speak out against China’s oppression in China and Tibet, we have lost all moral authority to speak on behalf of human rights anywhere in the world,” Pelosi told a cheering crowd in Dharmsala, India, seat of the Dalai Lama’s government-in-exile.

She dismissed China’s claim that the Dalai Lama was behind the violence in Lhasa, the Tibetan capital, as making “no sense.”

China’s response to last week’s riots in Lhasa drew world attention to its human rights record and threatens to overshadow its attempts to project an image of unity and prosperity ahead of the Aug. 8-24 Olympics in Beijing.

China’s official news agency issued an updated casualty toll late Friday for the unrest in Lhasa. Xinhua said 18 civilians and one police officer died and 623 people were injured.

Tibetal exile groups have said 99 people were killed – 80 in Lhasa and 19 in Gansu province. Casualty estimates are hard to confirm because China keeps tight control over information.

On Friday, Chinese authorities intensified a manhunt for the wanted suspects, posting their photos – taken from video cameras and security footage – on major Internet portals.

Shown under the heading of “Lhasa Public Security Bureau’s Wanted List of Criminal Suspects,” the 21 people are accused of endangering national security, and cited for beating, smashing, looting and arson.