Hundreds of Tibetans gathered in China's southwest to hold a vigil for a young Buddhist monk who set himself on fire, a rights group said Monday, in the latest self-immolation to hit the country.

The 18-year-old monk, identified as Nangdrol, set himself alight Sunday in Sichuan province's Rangtang county, where one Tibetan was reportedly shot dead by security forces last month, the International Campaign for Tibet (ICT) said.

Citing exiled Tibetan sources with contacts in the area, ICT said Nangdrol had died and his body was taken back to a local monastery. The information was confirmed by the London-based Free Tibet.

Monks did not comply with police orders to hand over the body and more than 1,000 people gathered to hold a vigil on Sunday evening, ICT said.

The group said the young Buddhist monk shouted "May HH (His Holiness) Dalai Lama live 10,000 years" and "Freedom for Tibet" when he set himself on fire.

An official surnamed Huang, who works for the finance department of the Rangtang government, denied the self-immolation and gathering had taken place.

"Everything is fine. The order is normal," he told AFP, adding there was a strong security presence.

"We have police and armed police on duty 24 hours a day. All government offices have staff on duty 24 hours a day," he said.

At least 22 people have set themselves on fire in Tibetan-inhabited areas of China over the past year -- mostly in Sichuan -- in what is seen as a desperate act by Tibetans protesting against perceived repressive Chinese rule.

Tensions have increased markedly this year, and western parts of Sichuan -- which borders the Tibet autonomous region and has a large population of ethnic Tibetans -- were hit by deadly bouts of unrest last month.

As a result, authorities have imposed virtual martial law in parts of the vast Tibetan-inhabited regions, increasing their surveillance of monasteries and cutting some phone and Internet communications.

China blames the Dalai Lama -- Tibet's exiled spiritual leader who is still widely revered in parts of the country -- of inciting the self-immolations in a bid to split Tibet from the rest of the nation.

Many Tibetans who travelled to India in January with valid passports to attend the Dalai Lama's teachings have been detained on their return to China and made to undergo political re-education, rights groups say.