Hundreds of paramilitary police forced an end to two days of ethnic clashes in western China, where at least 156 people died. Chinese state media say 1,434 people have been arrested.

Tensions have been simmering in Xinjiang province since two ethnic Muslim Uighurs were killed last month during a fight with Han Chinese co-workers at a southern China factory.

Many Uighurs feel marginalized in their homeland by the Han majority, and some militant members have fought for independence from China. As in Tibet, more and more Han are moving into the province.

"This is a vast region; it's actually about the size of Western Europe," Diana Lary, a professor of Chinese history at the University of British Columbia, told CTV News Channel on Monday.

"Xinjiang means 'the new frontier,' so it's a relatively new part of China. Until about 50 years ago, almost all of the inhabitants were Uighurs, who are closely connected across central Asia to the Turkish people. So they have really very little with the Han Chinese and they're Muslim by religion."

Police cracked down on the protests, chanting "Strike down the criminals" and ordering residents around Xinjiang University to stay off the roads. By nightfall, the protests had stopped.

An Uighur man in Kashgar city told The Associated Press he was among 300 demonstrators who were surrounded by police. A shouting match broke out, but there was no violence, he said.

On Sunday it was a different story, as violent street battles broke out in Urumqi, the capital of Xinjiang, between Uighurs and Han.

It was the worst violence China has seen in decades.

Canada's Foreign Affairs Minister Lawrence Cannon issued a statement Monday calling for restraint from both sides. He said Ottawa is "alarmed at reports of violence and high numbers of casualties."

"Dialogue and goodwill are required to help resolve grievances and prevent further deterioration of the situation," he added.

The Canadian government has advised anyone travelling to the region to exercise heightened caution and alert consular officials of their plans.

Exiled Uighur leader denies involvement

Rebiya Kadeer, the exiled leader of the Uighurs, has denied Chinese government accusations that she incited the deadly riots.

Kadeer is president of the Uyghur American Association and has lived in the U.S. since she was exiled in 2005 from China.

In an interview with The Associated Press she said she only called family to warn them to stay away from the protests.

Kadeer said she learned of the protests on the web and was concerned her family could be targeted by authorities.

Police and security forces set up checkpoints in Urumqi on Sunday, vowing to arrest those who were responsible for the riots that saw barricades overturned, vehicles and houses attacked and police targeted.

China's state media released video that showed protesters attacking other people and footage of dazed and injured victims -- who appeared to be members of the Han majority -- reeling from the violence.

Several hundred people were arrested but there has been no clear explanation of how so many people were killed. It is also unclear whether those killed were Uighurs, Han or both.

Beijing maintains that Uighurs incited the violence by starting a rampage that was urged on by Uighurs living in exile.

A government statement quoted by the official Xinhua news agency said the violence was "a pre-empted, organized violent crime. It is instigated and directed from abroad and carried out by outlaws in the country."

But Uighur advocates say police began firing indiscriminately on a crowd of peaceful demonstrators on Sunday.

Between 1,000 and 3,000 people had gathered in the regional capital to protest, when the situation apparently got out of control.

According to some reports, the situation became violence when the protesters refused to disperse. Some 260 vehicles were set on fire or damaged and 203 houses were damaged, according to Wu Nong, news office director for the Xinjiang provincial government.

Dolkun Isa, a spokesperson for the World Uyghur Congress in Germany, disputed the reports from Beijing and said the protest was actually 10,000 strong and that 600 people were killed, BBC reports.

Alim Seytoff, vice-president of the Washington, D.C.-based Uyghur American Association, called it a "dark day."

"We are extremely saddened by the heavy-handed use of force by the Chinese security forces against the peaceful demonstrators," Seytoff told AP.

"We ask the international community to condemn China's killing of innocent Uighurs. This is a very dark day in the history of the Uighur people," he said.

Some mobile phone service was disabled in the region -- a move seen as an attempt to prevent protesters from organizing further demonstrations.