The United States closed its Jakarta embassy and canceled a Sept. 11 commemoration, citing risks of a terrorist attack.

Embassy spokesman Stan Hersher on Tuesday also warned American citizens in Indonesia -- home to some hard-line Islamic groups -- to be "extremely cautious in the coming days" and to avoid facilities associated with the embassy.

"The U.S embassy has received credible and specific information that the American Embassy in Jakarta and the Consulate General in Surabaya are at risk of terrorist attack," Hersher said. He did not explain the nature of the risk or provide further details. Surabaya is a major city 375 miles west of Jakarta.

It is the second time since the Sept. 11 attacks that the heavily guarded embassy has been effected by security fears. In October, the public section of the building was shut down for two weeks.

The embassy's recreation club, which is used by many foreigners, was also closed Tuesday, guards at the complex said. However, the American-run Jakarta International School remained open.

Indonesia is the world's most populous Muslim nation, though most of its 210 million people dislike hardline interpretations of the faith.

In the days after the terrorist attacks in New York and Washington, small militant crowds rallied to protest outside the embassy.

One hard-line group threatened to round up and expel all U.S. citizens in protest at the U.S.-led attacks on Afghanistan. The threat came to nothing, however.