HONG KONG — Security forces opened fire on Tibetan protesters in western China on Monday, wounding at least 32 people and killing at least one of them in the largest violent confrontation in ethnic Tibetan areas of China since 2008, two Tibetan rights groups and the Tibetan exile government said.

Free Tibet, a group based in London, said tensions remained high into the evening after the shootings in Luhuo, which is known in Tibetan as Draggo and located in westernmost Sichuan Province, near the border with Tibet.

It was the second reported shooting of Tibetan protesters in the past week and a half. The previous one, on Jan. 14, in which two people were reported wounded, took place in Aba, also located in Sichuan Province and 100 miles northeast of Luhuo.

The combination of increasingly frequent confrontations and rising casualties during them “underlines how the situation is escalating,” said Stephanie Brigden, the director of Free Tibet.