The American Embassy in Islamabad says it has received information on possible terrorist attacks in the Pakistani capital in late December, especially during the Christmas and New Year holiday period.

The U.S. embassy's warning for American citizens says "possible targets include places of worship and shopping centers." Pakistani police and other officials were not available Saturday to comment on the U.S. warning. A Pakistani intelligence official says there is a "general threat perception" but no specific threats. He spoke on condition of anonymity because he is not authorized to speak to the media.

The U.S. warning says American citizens should "minimize the number and duration of trips" to crowded places such as markets, restaurants, hotels and places of worship.

American government personnel are under additional movement restrictions.