Everest closure - Taken from BBC online
Radio Free Asia reported that a number of monks were arrested on Monday after a march marking the 49th anniversary of a Tibetan uprising against Chinese rule.
The radio station, which is funded by the US government, said hundreds of monks took to the streets the following day to demand the release of their fellow monks - and were dispersed by tear gas.
Campaigners based outside China say protesters in Lhasa are being spurred on by rallies in other Chinese provinces and in India.
Matt Whitticase from the UK-based Free Tibet Campaign said protesters in Lhasa had been "emboldened" by the support they were receiving from across the world.
"Tibetans inside Tibet are aware that Tibetans in India are marching towards the Tibet border," he said.
Tibetan exiles in India began a march to the border with China on Monday - one of several events protesting against the Beijing Olympics and campaigning for an independent Tibet.
But Indian police arrested more than 100 of the exiles, saying their march breached an agreement between Delhi and the Tibet's India-based government-in-exile, headed by the province's spiritual leader, the Dalai Lama.
A surge in Tibetan activism could become a security headache for China in the run-up to the Beijing Olympics, correspondents say.
This week the Chinese leadership closed the north face of Mount Everest until after the Olympic Flame ascends in May, for fear that activists might use it to stage photogenic Tibet-related protests.