Police in Lhasa have arrested dozens of Tibetans suspected of supporting a campaign against celebrating the Tibetan New Year. The protest has been organised to commemorate last year’s anti-Chinese demonstrations.

Witnesses told The Times that uniformed and plainclothes police and members of the paramilitary People’s Armed Police were involved in the sweep, which began on Monday. They raided tea houses, which are popular with young Tibetans, and picked up people of all ages in the street.

Many of those detained were accused of “spreading rumours”, sources in the Tibetan capital said.

The sweep appeared to have begun in the district around the Ramoche temple in the old city, where peaceful demonstrations in support of the exiled Dalai Lama burst into violence on March 14 last year, with protesters rampaging through the streets, setting fire to shops and offices. At least 18 people died in the violence and, over the next few days, dozens of demonstrations swept neighbouring provinces and troops opened fire on protesters.

Tibetans campaigning against celebration of the New Year, or Losar, on February 25, say that the day should be a time of remembrance. They have issued appeals on the internet and sent text messages putting their case.

One text message says: “To mourn those Tibetans who died in 2008, those many heroes who gave their lives, to show sympathy for all Tibetans, we should have no New Year and join hands to show our solidarity.”

Hand-made posters have been pasted on walls in ethnic Tibetan areas of western China urging people not to celebrate. One reads: “One thousand people have been arrested, 1,000 people have disappeared. We others, Tibetans who are living safely, if you have a good heart please do these two things. Do not sing, dance or play and do not set off fireworks. These two actions only. Let us remember the dead and pray for the living.”

In Lhasa, government employees have been ordered by the authorities to provide guarantees that they will report to work every day, stay in their offices and not take part in any disturbances. They have been told to make sure that their family members comply and have been warned that those who disobey will be severely punished, sources in Lhasa said.

“Lhasa hasn’t been this tense since the arrests in March and April last year,” one source said. “The atmosphere in the streets is almost as frightening.”

In neighbouring Qinghai province, officials visited the homes of Tibetans asking them to sign a document guaranteeing no repeat of last year’s violence and to celebrate the new year.

In Gansu province, ethnic Tibetan civil servants were given fireworks worth 100 yuan (£10) to set off during the Chinese New Year festivities. It was not clear if similar handouts would be made for the Tibetan festival.

Officials also distributed fireworks to Tibetan families in the Aba district of neighbouring Sichuan province, where protests in March were the most widespread. They were asked to light the fireworks on hillsides around temples and monasteries in return for rewards. Some Tibetans have put pressure on others to defy the order, threatening to ostracise anyone who joins the celebrations. “No one will go to their weddings, funerals or parties,” said one Tibetan source.

The defiance underscores the level of discontent that continues to simmer in many Tibetan communities. Since mid-January, police have scoured Lhasa for possible troublemakers in a new Strike Hard campaign and detained 81 people, including two found to have "reactionary" songs – probably praising the Dalai Lama – on their mobile phones.

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