A US tourist has been stabbed to death by a Chinese man in central Beijing, officials have said.
A second tourist was badly hurt in the attack at the Drum Tower monument. The pair are relatives of a US Olympic volleyball team coach.
The assailant then committed suicide by jumping from the 13th Century landmark, officials say. The motive is not known.
The BBC's Quentin Sommerville says murders, especially targeting foreigners, are very rare in China.
The attack happened despite high security across the capital on the first full day of Olympic competition, with more than 150,000 police and other personnel on patrol.
Officials named the Chinese man as 47-year-old Tang Yongming, from the eastern town of Hangzhou, but said they had no idea what had motivated his attack or suicide.
"While at the Drum Tower in central Beijing, the two family members were stabbed during an attack by what local law enforcement authorities have indicated was a lone assailant," the International Olympic Committee said in a statement.
Reports say the tourists' guide was also hurt.
On the scene
The attack happened at the popular tourist attraction some three miles (5km) from the main Olympics site, at around midday local time.
The scene of the attack
An estimated 450,000 foreign tourists are expected to be in Beijing for the Games, which opened with a lavish ceremony on Friday evening.
The attack happened the day before US President George W Bush - in Beijing to attend the Games - is due to meet Chinese President Hu Jintao.
A US embassy spokesman said he was aware of the reports of the attack.
"I can tell you that we are working with the family and the Chinese authorities as we speak," Richard Buangan told AFP news agency.
US embassy officials have been despatched to the hospital where the two injured attack survivors have been sent.
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