Swiss police are investigating threatening letters sent to the International Olympic Committee (IOC) headquarters in Lausanne. The letters reportedly warn members of attacks if they vote for Beijing to host the 2008 Olympic games.
The Chinese capital is the current favourite to win the vote, which takes place in Moscow on July 13. But Beijing's bid is strongly opposed by some human rights groups.
IOC director general Francois Carrard said the threatening letters were allegedly sent by a "faction of the Tibetan Youth Congress". The Congress is an organisation of exiled Tibetans, which seeks Tibet's complete independence from China.
"We have passed them on to the police and they are investigating," Carrard said. "We cannot ignore them. The letters say 'Watch Out. Take us seriously'."
Tibetan exiles staged a demonstration against Beijing's bid outside the IOC headquarters last month before a key report on the five candidate cities was published.
Beijing is competing to host the 2008 games with Paris, Toronto, Istanbul and Osaka.
But observers believe China is almost certain to win the nomination after it missed out on the 2000 games, which were awarded to Sydney. The 1989 Tiananmen Square massacre was believed to have helped derail Beijing's last bid.
Security is expected to be tight at the Moscow vote. "I expect the security to be well run," Carrard said.
swissinfo with agencies
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