The U.S. State Department has updated its "worldwide caution" for Americans overseas, saying it "remains concerned about the continued threat of terrorist attacks, demonstrations and other violent actions against U.S. citizens and interests."
The department said Friday authorities believe there is "an increased likelihood of reprisal attacks" for the U.S.-led airstrikes on Islamic State militants, especially in the Middle East, North Africa, Europe and Asia. Friday's statement identified "U.S., Western and coalition partner interests" as being at risk.
The State Department warned that extremists may elect to target private locations, such as sporting events, hotels, clubs, restaurants, shopping malls and other tourist destinations where U.S. citizens gather in large numbers, including during holidays.
It also issued a reminder of the potential for terrorist attacks on public transportation systems, such as subway systems and air travel.
The statement noted that kidnappings and hostage events involving U.S. citizens "have become increasingly prevalent," as the Islamic State group, al-Qaida and al-Qaida affiliates have increased attempts to finance their operations through ransom money.
It said U.S. citizens in Iraq "remain at high risk for kidnapping and terrorist violence," while "no part of Syria should be considered immune from violence."