According to its magazine, al Qaeda is calling on terrorist affiliates to set off car bombs in major U.S. cities.
FOX News Radio's Tonya J. Powers reports in our national security update "Securing America":
New York, Washington DC, and Los Angeles... Just some of the locations mentioned as targets in the latest edition of al Qaeda's "Inspire" magazine.
It comes nearly a year after the Boston Marathon bombing, just as the city is putting new security measures in place for this year's race.
"Inspire" magazine is the same publication that detailed how to make pressure cooker bombs, which were carried in backpacks and used in last year's Boston attack.
Boston Police Commissioner William Evans says people who show up with backpacks have been warned.
(Evans) "If they're gonna bring large bags, everyone has to realize, they're gonna be subject to search."
Commissioner Evans says that's what's behind the bag crackdown.
(Evans) "After what happened last April, and what this city was put through, that we're gonna strongly discourage them... Not to bring it."
The magazine urges jihadists to target heavily populated events like political rallies and sporting events, both in the U.S. and abroad.
Would-be bombers are also urged to consider launching attacks during election season and between Christmas and New Year's.
Tonya J. Powers, FOX News Radio.