Chinese police have warned that Islamic militants could be planning an attack on luxury hotels in Beijing in the coming week, the US embassy has said.
Expensive hotels in Beijing could be at risk
The authorities pledged to investigate the threat and take appropriate action, the embassy said in a statement.
The warning comes 10 days before US President George Bush visits Beijing.
China is often accused of exaggerating the threat of Islamic militancy to justify its crackdown on groups such as its Uighur minority.
"The embassy has learned that Chinese police advised hotels that Islamic extremist elements could be planning to attack four- and five-star hotels in China some time over the course of the next week," the statement from the US embassy in Beijing said.
"American citizens visiting Chinese four- and five-star hotels should review their plans carefully, remain vigilant with regard to their personal security, and exercise caution," it added.
The statement did not specify whether the threat came from extremists inside or outside China.
But Beijing has often warned of a threat from the Muslim Uighur community in the western Chinese region of Xinjiang.
Many Uighurs campaign for an independent homeland in the region, which they would call East Turkestan, and resent the recent and large-scale influx into the region of Han Chinese settlers.
China brands these separatists as terrorists and said in September that more than 260 terrorist acts had been committed in Xinjiang in the past two decades.
Critics say China has been using its support for the US-led war on terrorism to justify a crackdown on the Uighurs.
Human rights groups cite arbitrary arrests, closed trials and the use of the death penalty against alleged militants in Xinjiang.