BEIJING, Jan 6 (Reuter) - Chinese authorities, shaken by a bombing in Lhasa last month, have tightened security across Tibet in the run-up to the Himalayan region's New Year next month, the Tibet Daily said.

``In our region, there is not a single unit or department that can sleep soundly or relax its vigilance in the struggle against separatism,'' Gyamco, a vice-chairman of Tibet's regional government, was quoted as saying in an edition seen in Beijing on Monday.

Authorities have launched a manhunt across Tibet and offered a reward of one million yuan ($120,000) for the arrest of those responsible for a bomb set off on Christmas Day outside city government offices in Lhasa, the Tibetan capital.

No casualties were reported, but the bomb the largest so far by anti-Chineseactivists in the restive region caused widespread damage, shattering windows 100 metres (yards) away, officials have said.

Gyamco ordered all departments to be staffed round-the-clock in the run-up to the Tibetan New Year on February 8 and called for vigilance to prevent more acts of sabotage, the newspaper said in its December 28 edition.

``Our struggle against the Dalai Lama clique is an intense and complicated class struggle and an unshirkable political responsibility of leaders at all levels,'' Gyamco said.

China blames followers of Tibet's exiled god-king, the Dalai Lama, for anti-Chinese unrest that erupts sporadically in the Himalayan region that borders India.

The Dalai Lama, who won the Nobel Peace Prize in 1989 for his non-violent campaign to win autonomy for his homeland, says he wants autonomy and freedom of worship in the deeply Buddhist region. He fled China into exile in India in 1959 after an abortive uprising against communist rule.

Several much smaller bombs have been been set off in Lhasa in the past two years, including one in 1995 that slightly damaged a plaque donated by Beijing and another last March outside the headquarters of the Tibet regional government.

Lhasa's Communist Party deputy secretary Hou Jianguo vowed to track down the saboteurs responsible for the Christmas Day bombing at all costs, the newspaper said.

``We are determined to solve this case as early as possible and at all costs,'' Hou said.

Authorities would continue a campaign to indoctrinate monks and nuns at lamaseries to be ``patriotic'' and pledge allegiance to the Chinese government, the official said.

Chinese officials have insisted there was little doubt that the Christmas Day blast was politically motivated and carried out by followers of the the Dalai Lama.

Last week, Tibet's government-in-exile in Dharamsala, in northern India, denied the Chinese allegation, saying the bombing could have been carried out by China as an excuse to crack down on dissent.

Tibet has been rocked in recent years by sporadic, sometimes violent, anti-Chinese unrest with monks and nuns often at the forefront of demonstrations for independence.

The exiled government says it opposes violence and remains committed to a negotiated political settlement.