The State Department says terrorists may want to disrupt this summer's Olympics in China and warned of a heightened risk of terrorist attacks there in the coming months.

In a travel alert Friday, the department said that despite increased Chinese security measures, Americans who plan to attend the Games or who live in China should use caution at all times, especially in large crowds.

"There is a heightened risk that extremist groups will conduct terrorist acts within China in the near future," the alert said. "In light of these security concerns, U.S. citizens traveling in China are advised to use caution and to be alert to their surroundings at all times, including at hotels, in restaurants, on public transportation and where there are demonstrations and other large-scale public gatherings.

"American citizens are strongly encouraged to maintain a high level of vigilance, be aware of local events, and take the appropriate steps to bolster their personal security," it said.

The alert was issued shortly after the international police organization Interpol issued a similar warning, saying that violence surrounding the games which begin in August is a real possibility.

Interpol chief Ronald Noble said in a statement earlier Friday that potential attacks could involve efforts to block transportation routes, interfere with competition, assault athletes or destroy property during the Olympics.

Chinese officials have said that terrorism is the biggest threat to the Aug. 8-24 Olympic Games and has called for closer international cooperation to prevent possible incidents.

"When thwarted attacks are coupled with the recent violent protests viewed by us all worldwide, prudence requires us to recognize the real possibility that groups and individuals could carry on their protests at the actual Games," said Noble, who spoke at an international security conference.

China's generally secretive police agencies have sought advice on Olympic security from the United States, Germany, Israel and other foreign governments.