China has closed Mount Everest to climbers amid fears that activists could disrupt the Olympic torch ascent of the world’s highest peak.

The announcement that Chinese authorities had halted access to its side of the mountain that straddles the border between Tibet and Nepal came amid reports of a third day of protests by Tibetan monks around Lhasa, the capital of Tibet.

In a letter to expedition companies, the China Tibet Mountaineering Association said: “Concern over climbing activities, crowded climbing routes and increasing environmental pressures will cause potential safety problems in Qomalangma \ areas.” It added: “We are not able to accept your expedition, so please postpone your climbing.”

The decision will be a huge disappointment to mountaineers already preparing for the season and will hit the incomes of the bearers, guides and sherpas.

Carrying the Olympic torch to the 29,035ft (8,840m) summit has been hailed by the Games host city, Beijing, as one of the grandest feats of the event. Running the relay through one of China’s most restive regions, where many Tibetans chafe under Beijing’s rule, also risks politicising the Games.

The order coincides with the annual climbing season in April, May and the first weeks of June. A mountaineering official said that a record number of climbers attempted to reach the summit from the Tibetan side last year.

Officials have been rattled about the torch relay since an incident last April when four American pro-Tibet activists made their way to Everest base camp on the Tibetan side and unfurled a banner reading “One World, One Dream, Free Tibet 2008”. The group was swiftly deported.

The leadership is likely to be very anxious about stability in the Himalayan region as the Olympics approach, after a series of demonstrations by monks on a scale that has not been seen in nearly 20 years.

Monks at Ganden monastery, a hilltop eyrie 30 miles (50km) from Lhasa, staged a protest yesterday and armed paramilitary police were sent in to restore order, Tibetan sources said.

The unrest has now spread to the third of Tibet’s “Three Great Monasteries”. Witnesses described soldiers firing teargas on Tuesday to disperse more than 600 monks as they tried to march out of the Sera monastery on the edge of Lhasa. The monks were forced to a halt at the gates after police called in the military.

The monks shouted “Release our people”, demanding the return of 11 of their number detained when they staged an anti-Chinese protest in front of the Jokhang Temple, the holiest site in Tibetan Buddhism, in the heart of the city on Monday. That protest coincided with demonstrations by about 500 monks from the sprawling Drepung monastery outside Lhasa.

The pro-independence demonstrations in support for the exiled Dalai Lama are the largest since the anti-Chinese riots in March 1989, when Beijing imposed martial law.

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