The US Embassy in Islamabad has issued a warning saying it has received information regarding possible terrorist attacks in the federal capital in late December."Possible targets include places of worship and shopping centers," the US embassy said in a statement. However, the embassy did not delve into details regarding the information that led it to issue the warning on Friday.The embassy warned Americans to avoid busy places during the Christmas and New Year period. American citizens should "minimise the number and duration of trips" to crowded places such as markets, restaurants, hotels and places of worship and other locations where large numbers of people congregate, the warning said. American government personnel are under additional movement restrictions in coming weeks, including religious venues and large shopping centers.The Associated Press could not reach police and other officials for comment. However, an intelligence official speaking on the condition of anonymity said there is a "general threat perception" but no specific threats.In August, the US State Department warned Americans against all non-essential travel to Pakistan, citing the threat of foreign and domestic terrorist groups operating throughout the country. Further, in July, gunmen shot and killed a local employee of the US Embassy in Islamabad.This article originally appeared on ABC News