An 18-year-old monk has died after setting himself on fire in south-west China, in the latest of dozens of self-immolations by Tibetans in the past 16 months, the Tibetan government-in-exile said.

Lobsang Lozin, from the Gyalrong Tsodun Kirti monastery, set himself alight around noon and local Tibetans blocked a bridge to prevent police from moving in, according to the exiled government based in Dharamsala, India.

A photo shared by the government-in-exile showed a blackened body lying on the ground engulfed in flame. Three people were praying as they lowered their heads and put their palms together.

The various reports on Lozin's death differed on where he died, but the Kirti monastery has been a centre of dissent against China for years, and two of its monks died of self-immolation on 30 March.

The Chinese government's intense crackdown has included "re-educating" monks and increasing security and surveillance at the monastery and the surrounding area.

The monastery is in the Ngaba Tibetan autonomous prefecture in Sichuan province.

The International Campaign for Tibet says 42 Tibetans have self-immolated since March 2011. The Chinese government has confirmed some but not all of such protests and gave no information on Tuesday's death.

Activists say the self-immolations are protests against Beijing's heavy-handed rule in the region. China has blamed the Dalai Lama for inciting them, which the exiled spiritual leader denies.