The State Department has released a worldwide travel alert for Americans, citing increased terrorism threats worldwide and advising U.S. citizens to “avoid large crowds or crowed places,” especially during the holiday season.

The Monday alert, which also warned Americans of the risks of using public transportation and attending theater and sporting events, is effective for three months and only expires on Feb. 24, the State Department said.

The alert comes 10 days after Islamist terrorists killed 130 people in several Paris locations and while Brussels, the capital of neighboring Belgium, is on lockdown.

“Authorities believe the likelihood of terror attacks will continue as members of ISIL/Da’esh return from Syria and Iraq,” the State Department said, going on to note the additional possibility of lone wolf and copycat attacks.

The alert, which cited no geographic boundaries, said “U.S. citizens should exercise vigilance when in public places or using transportation. Be aware of immediate surroundings and avoid large crowds or crowed places. Exercise particular caution during the holiday season and at holiday festivals or events.”