The U.S. warned American travelers Friday to be "extra cautious" in a rare worldwide travel alert.
In the alert, the State Department warned travelers that terrorists may target civilian facilities, including "hotels, shopping areas, places of worship, and schools, among other targets." The attacks could happen "during or coinciding with this holiday period," officials added.
The alert, which is in effect for three months, mentions the lone wolf attack in Sydney that left three people dead on Sunday. However, it does not cite any specific pending threat and merely cautions travelers to "remain alert to local conditions and for signs of danger."
Worldwide travel alerts have been used sparingly in the past. Friday's alert, which ends March 19, is the first issued in 2014. The State Department did issue a series of other alerts and warnings this year in response to threats from terrorism, disease, international drug trade, and weather, but none of those warnings covered the entire globe.
The last time the U.S. issued a worldwide alert was in August 2013 and came in response to threats from al-Qaeda.