URUMQI, China — The Olympic torch started its relay route today through China's restive western region of Xinjiang amid cheering crowds and heavy security.

Torchbearers high-fived each other as they passed the flame on the streets of the capital Urumqi, guarded by a phalanx of security agents who jogged along on either side. Carefully controlled crowds waving the national flag and shouting "Go China!" stood behind metal barriers and were closely watched by police and troops.

While the Olympic torch has had a smooth run in China — uninterrupted by the protests over Tibet and human rights that followed parts of its international tour — stops in Xinjiang and Tibet are the most sensitive.

Overseas activists have criticized Beijing for using the relay to show China's control over the restive areas.

Like Tibet, Xinjiang is a region with a culture that is distinctly different from that of China's ethnic Han majority. The Muslim, Turkic-speaking Uighurs have long sought independence, waging a low-intensity struggle against Chinese rule. Many have been sentenced to long prison terms or death on separatism charges. China's ethnic Han people dominate the region's economy and government.

Today, the Olympic flame began its trip through Xinjiang after a minute's silence for the May 12 earthquake that devastated Sichuan province. More than 200 torchbearers will carry the flame across the city, 12 of them Muslim women.

A Uighur boxer started the relay and another torchbearer performed a traditional Uighur dance during her turn — Beijing's way of showing it is sensitive to the region's culture.

But authorities also were strictly monitoring the event, with armed police patrolling Urumqi's Muslim quarter on Monday night and sniffer dogs checking the 7.8-mile route through the city.

Roads surrounding the route were closed early today and only hand-picked bystanders with credentials were allowed to watch from the streets.

All buildings and hotels were told to keep their windows closed during the day to prevent unwanted displays of defiance.

"On the day of the relay, over 100,000 chosen citizens will be shouting and cheering on the streets," Li Guangming, party secretary of the Xinjiang Sports Administration, was quoted as saying in Monday's Xinjiang Daily newspaper. "However, given that too many people will cause the rise of unsafe elements, we suggest that everybody else watch the relay live on TV at home."

On at least three occasions this year, authorities say they foiled plots by Xinjiang separatists that targeted the games either directly or indirectly, including alleged attempts to crash an airliner and kidnap athletes and journalists.

During its three-day trip, the torch will go on to the far western city of Kashgar, once a stop on the ancient Silk Road of China, and two other cities in the region before moving to Tibet.

Before it returns to Beijing on Aug. 6, two days ahead of the opening ceremony for the games, the Olympic torch will have crossed every region and province of China, and a separate torch reached the summit of Mount Everest early last month.