"What we know is that the incident took place on Saturday, and that several monks raised the Tibetan flag, and pulled down a Chinese flag and they were arrested."

"The protest was peaceful, and not violent."

The demonstrations come a week after politically-sensitive anniversaries in which Tibetan exiles marked 50 years since a failed uprising against Chinese rule and one year since violent clashes between protesters and Chinese authorities in Lhasa and other Tibetan areas.

There has been an increased security presence in the area since the crackdown last year.

But in recent weeks, a monk set himself on fire at the Kirti monastery in the western province Sichuan and a bomb was thrown at a government office, but caused no casualties.