Incantations ring out at Mongolia's largest monastery as worshippers pray alongside pictures of the Dalai Lama, whose 90th birthday on Sunday has raised fresh questions about the future of the 600-year-old Tibetan spiritual institution.

The Dalai Lama has announced that he will have a successor after his death, continuing a centuries-old tradition that has become a flashpoint in the struggle with China’s Communist Party over Tibet’s future.

The Dalai Lama has announced that he intends to reincarnate, paving the way for a successor to take on a mantle stretching back 500 years after his death.