As millions of Americans are getting ready to head out of town for the holidays, the State Department put out a worldwide travel alert.
"Current information suggests that ISIL [Islamic State], al-Qaida, Boko Haram, and other terrorist groups continue to plan terrorist attacks in multiple regions," the department said in issuing the warning Monday.
The FBI maintains there is no specific, credible terrorist threat to the U.S., but local and federal law enforcement are on high alert ahead of the Thanksgiving holiday and the Black Friday shopping extravaganza that follows, bringing out travelers and shoppers in full force.
Transportation Security Administration workers, who typically process 2 million people a day, will see a 40 percent increase in passengers over the holidays, the TSA said.
In New York, additional police officers will patrol major rail hubs. In a show of force, police on Sunday ran through active shooter drills in the city's subway system.
New York Gov. Andrew Cuomo said on Monday there's a new app residents can download that will help enhance the state's ability to fight terrorism. The new campaign, called "See Something, Send Something," is designed to encourage New Yorkers to report suspicious activity.
FILE - A man sleeps at the Los Angeles International Airport.
"We have stepped up our preparedness in the aftermath of the Paris attacks, and we continue to remain vigilant against those who seek to spread fear and violence," Cuomo said in a statement.
An estimated 46.9 million people will travel 50 miles or more from home during the Thanksgiving holiday, an increase of 300,000 over last year and the most since 2007, according to AAA Travel.
The vast majority of those – 42 million Americans – will be driving.
Some 3.6 million Americans are flying to their holiday destinations, a 0.1 percent increase from last year.
AAA Travel defines the Thanksgiving holiday period this year as Wednesday, November 25, to Sunday, November 29.