Beijing - Officials in south-western China's Sichuan province have persuaded Tibetans to end a boycott of spring farming in support of the exiled Dalai Lama, Chinese state media and US-funded Radio Free Asia reported on Thursday.

The officials in Sichuan's Kardze (Ganzi) prefecture visited Tibetan families in farming villages after a boycott began in early March, the Chinese government's Xinhua news agency said.

The local government posted open letters "trying to persuade the peasants back to farming" following calls for a boycott in support of the Dalai Lama's return to China, the agency said.

Radio Free Asia quoted sources as saying the Chinese officials, accompanied by police and soldiers, "forced Tibetan farmers into their fields" and threatened to confiscate the land of some farmers who joined the boycott.

The broadcaster quoted the sources as saying more than 100 government workers, police and troops arrived in the village of Kara on March 20 to escort Tibetan farmers to their fields.

Yeshe Dorje, a former Kardze resident based in Australia, told the broadcaster that the boycott campaign had intensified after police detained six Tibetan protestors at different times on March 16.

Following the arrests, several posters were put up in Tibetan villages near Kardze town to support the boycott and warn of "serious consequences" for those who failed to join it, Dorje was quoted as saying.

Xinhua quoted Lodro, the deputy director of agriculture in Kardze prefecture, as saying some Tibetans were threatened with death and the destruction of their homes if they ignored the farming boycott.

Lodro said spring ploughing had "gradually recovered from south to north" in Kardze, where more than two-thirds of the 800,000 residents rely on agriculture.

Both reports said a small bomb exploded last week in Kardze's Dotso town at the home of a Tibetan official accused of collaborating with the government. They did not say if anyone was injured in the attack.

The farming boycott came amid weeks of small protests and civil disobedience in Tibetan areas of China, which began with calls to boycott celebrations of the Tibetan lunar new year in late February.

In one the latest incidents, two nuns were detained on Tuesday after scattering leaflets supporting the Dalai Lama and calling for Tibetan independence outside the Kardze police headquarters, according to reports by Radio Free Asia and the Indian-based radio station Voice of Tibet.

The government has also closed major monasteries in Lhasa, the capital of the Tibet Autonomous Region, ahead of a holiday to mark the newly declared "Serfs' Emancipation Day" on March 28, the reports said.

Paramilitary police have sealed off almost all Tibetan areas of China to foreign journalists and tourists for nearly one month, while the government has tightened border security and cut off some text messaging and other mobile telephone services in Lhasa and other Tibetan areas.

The crackdown is designed to ensure there are no repeats of the widespread anti-Chinese protests in Tibetan areas last spring.

Rioting broke out in Lhasa on March 14 last year, four days after the 49th anniversary of a failed Tibetan uprising against Chinese rule. (dpa)