BEIJING — Chinese mountaineers made final preparations yesterday to take the Olympic flame up Mount Everest in a grand but contentious feat that is being accorded an unusual mixture of fanfare and secrecy.

As China marked 100 days before the start of the Olympics, state-run television began the first of what were billed as elaborate and technically difficult live broadcasts from Everest’s base camp for the journey up the world’s tallest peak. Mountaineers were completing the setup of a staging point at 27,390 feet for the final assault on the 29,035-foot summit, Chinese Central Television reported.

There was no word on the flame’s whereabouts or those of the 31-member team that would go to the summit. Nor was there any news on which members would ascend to the peak or when.

The Web site of Beijing Daily likened the lack of information to a “mysterious veil that has surrounded base camp.”

Some press reports had speculated that the climb could come as early as yesterday — when the countdown clock in Beijing marked 100 days to the August 8-24 games — or today — the May Day holiday.

A brewing storm made a climb in the next three days unlikely, the Xinhua News Agency reported late yesterday, the expedition’s weather expert at base camp, citing Yang Xingguo.

To commemorate the 100-day mark, Beijing held a mini-marathon outside the nearly completed National Stadium, and a song gala, where actor Jackie Chan joined other celebrities to sing “Beijing Welcomes You,” which was written for the event.

A senior Communist Party leader, Jia Qinglin, urged all Chinese “to pool our patriotic passion to accumulate a mighty force that could overcome all difficulties to in a bid to hold a successful Olympics.”

Meanwhile, the Chinese and foreign reporters at Everest base camp wait. Still billed as a spectacular event, the Everest climb is being given mixed treatment. With the torch relay dogged by protests and Beijing’s criticized rule in Tibet drawing scrutiny after demonstrations this spring, organizers have placed a premium on security.

The Everest flame was specially designed to burn in frigid, windy, oxygen-thin Himalayan air. It is a sister flame to the one that made its way around the world and reached Hong Kong yesterday, returning to Chinese territory after a contentious month abroad.

Free speech is protected in Hong Kong, the British colony that returned to China’s rule 11 years ago, but Chinese leaders and Olympic organizers hope the worst is behind them.

While it may face some protests when it is run through Hong Kong and neighboring Macau tomorrow and Saturday, the torch then moves to less-contested territory for a three-month journey across China.

[Also yesterday, the Los Angeles Times reported that a photo that seems to show Chinese paramilitary forces carrying monks’ robes provides conclusive evidence, those spreading it through e-mail claim, that the Chinese staged Tibet riots last month to justify a government crackdown. But the photo, widely distributed via the Internet, appears likely to be a 7-year-old image taken during a film shoot.]