President Hu Jintao said development and stability were key for Tibet
China's President Hu Jintao has spoken of the need for a "Great Wall against separatism", on the eve of the 50th anniversary of Tibet's failed uprising.
He told Tibetan leaders in Beijing that China's "unity" needed to be protected and Tibet's long-term security secured.
His comments come as security is stepped up in Tibetan areas for Tuesday's anniversary of the failed revolt against Chinese rule.
Two home-made bombs exploded in a Tibetan part of west China on Monday.
No injuries were reported, but the blasts damaged two vehicles - one a police car - in Qinghai province.
Last year, protests in Lhasa to mark the anniversary led to deadly anti-Chinese riots that spread across Tibetan regions - the worst unrest there for 20 years.
"We must build up a Great Wall in our fight against separatism and safeguard the unity of the motherland, and push Tibet's basic stability towards long-term stability," Hu Jintao said.
China says Tibet was always part of its territory
Tibet enjoyed long periods of autonomy before the 20th Century
China launched a military assault in 1950
Opposition to Chinese rule led to a bloody uprising which began on 10 March 1959
Tibet's spiritual leader, the Dalai Lama, fled days later and crossed into India on 31 March 1959
He was speaking to Tibetan delegates of the National People's Congress, China's legislative body, which is currently holding its annual session in Beijing.
"Tibet should fully implement the important tasks of development and stability and ensure that the economy develops rapidly and that state security and Tibetan society remain stable," he told them in comments broadcast on state television.
Thousands of troops and paramilitary police are said to have been deployed in Tibetan-populated regions amid fears of fresh violence during the sensitive anniversary period.
Beijing says it has tightened its border controls in those areas ahead of "expected sabotage activities by the Dalai Lama clique".
"We will firmly crack down on criminal activities in Tibet's border area that pose a threat to China's sovereignty and government," border control official Fu Hongyu was quoted as saying.
Foreign tourists have also been barred from travelling to Tibet during the month of March, according to travel agencies.
Monday's blasts are reported to have occurred in Golog, a Tibetan autonomous prefecture in Qinghai province.
A police car and a fire engine were hit by "minor explosions" about 0200 local time, according to authorities quoted by the Xinhua news agency.
It followed a dispute at a timber yard between the authorities and dozens of local residents angered after police stopped a timber lorry for a security check, state media reported.
China does not allow foreign journalists unrestricted access to Tibet or restive areas surrounding it, making it extremely difficult to verify reports from the region.
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