BEIJING  The Dalai Lama delivered one of his harshest attacks on the Chinese government in recent times on Tuesday, saying that the Chinese Communist Party had transformed Tibet into a “hell on earth” and that the Chinese authorities regarded Tibetans as “criminals deserving to be put to death.”

“Today, the religion, culture, language and identity, which successive generations of Tibetans have considered more precious than their lives, are nearing extinction,” said the Dalai Lama, 73, the spiritual leader of Tibetans.

He spoke in Dharamsala, India, the Himalayan town that is the seat of the Tibetan government in exile. Tibetans outside of China and their supporters held rallies around the world on Tuesday to mark the 50th anniversary of a failed Tibetan uprising against Chinese rule. China crushed the rebellion, forcing the Dalai Lama to flee to India.

The furious tone of the speech may have been in reaction to a new clampdown by China on the Tibetan regions. The Dalai Lama may also have adopted an angry approach to placate younger Tibetans who have accused him of being too conciliatory toward China. He advocates genuine autonomy for Tibet and not secession, while more radical Tibetans are urging him to support outright independence.