BEIJING (Reuter) - China's restive Tibet region appeared certain Sunday to fall under the shadow of a renewed campaign of intimidation after a music student was jailed for 18 years for spying and a bomb rocked the capital.

"The bomb attack, especially such a big explosion, is a real slap in the face," said one Tibet observer who declined to be identified. "The authorities really don't know any other way but the knee-jerk crackdown response."

A senior local government leader signaled that a new round of intimidation in the deeply Buddhist Himalayan region was essential to tackle such challenges to Beijing's sovereignty.

"We should wage a tit-for-tat struggle against the Dalai (Lama) clique's sabotage," Gyamco, vice chairman of the regional government, was quoted by local radio as telling a Friday meeting of party government officials in Lhasa after the Christmas Day blast.

"We should, once again, stage another campaign across Tibet to thoroughly expose and criticize the Dalai clique, heighten our alertness and strengthen preventive measures so as to keep the situation stable," the radio quoted him as saying.

The explosion was certain to trigger further official rhetoric against the Dalai Lama, Tibet's exiled god-king, whom Beijing accuses of fomenting anti-Chinese unrest in the strategic mountainous region that borders India, analysts said.

The Dalai Lama, who won the Nobel Peace Prize in 1989 for his non-violent campaign to win autonomy for Tibet, says he wants self-government and freedom of worship in the region.

He fled China in 1959 after an abortive uprising against Beijing rule.

Police had set up new checkpoints on the road west from Lhasa, visited hotels to question Tibetan guests, particularly exiles from India, and begun house-to-house questioning of young Tibetan men, the London-based Tibet Information Network said.

Diplomats said the extraordinarily harsh prison sentence meted out to music scholar Ngawang Choephol underlined the determination of authorities in the region to stamp out even the smallest activity that lacked an official sanction.

Ngawang Choephel, 30, was jailed last Friday by a court in Tibet's second city, Xigaze, for 18 years for spying, in one of the harshest sentences ever meted out in the region.

The student, a former Fulbright scholar in the United States, disappeared into China's security limbo in August 1995 while traveling in Tibet to produce an amateur documentary film about traditional music and dance.

The young scholar confessed to having been sent to Tibet by "the Dalai (Lama) clique" on behalf of an unnamed foreign country to conduct espionage, local radio said in a thinly veiled reference to the United States.

Washington voiced concern at the sentence, and said it knew nothing of his activities other than making a documentary.

"It appears to mean the end of any sense that China is susceptible to the international community on human rights issues," Robbie Barnett of the Tibet Information Network said after hearing of the sentence.

"They now feel confident to use counterespionage laws against political offenders," he said late on Friday.

But with the largest bomb explosion yet reported in Tibet rocking Lhasa before dawn on Dec. 25, a renewed crackdown on anti-Chinese unrest appeared inevitable.

One Tibetan government official reached by telephone in Lhasa on Sunday said he could not comment on the bomb blast because he was too busy conducting a rectification and discipline drive in Lhasa's temples and monasteries.

The bomb exploded outside the main city government office in Lhasa, shattering windows in a 100-yard radius and prompting officials to condemn the blast as "an appalling act of terrorism." They said no one was wounded in the explosion.

"The act of terrorism...fully demonstrates that the Dalai (Lama) clique has cast off its previously so-called peaceful disguise to openly oppose the people of Tibet and has reached a point when it puts up a last-ditch struggle," local radio said