Counterterrorism officials are tracking threats to the U.S. and Europe from al Qaeda and affiliated groups during the holiday season but have not yet seen evidence of specific plots aimed at the U.S., authorities said.
The FBI and Homeland Security Department have alerted state and local law enforcement to be wary of suspicious behavior and to regularly change security measures to interfere with any terrorist plans. The warning was sent in a Dec. 15 bulletin obtained by The Associated Press. It did not include information about specific plots or intelligence.
On Dec. 11, aon a pedestrian street in Stockholm, Sweden, killing himself and injuring two other people. Iraqi officials said that captured insurgents had revealed this week that the suicide bombing was part of against the U.S. and Europe during the Christmas season.
Even before the revelations from the captured Iraqi insurgents, U.S. counterterrorism officials were tracking threat streams from al Qaeda operatives hiding in Pakistan and Yemen.
There is specific intelligence of attacks being planned against Europe during the holiday season. While intelligence officials have not uncovered specific details of threats aimed at the U.S., they cannot be ruled out, according to U.S. officials speaking on condition of anonymity to discuss security matters.
Still, the spate of attempted attacks against the U.S. in the past year - particularly the- has U.S. officials on high alert.
"We are concerned these terrorists may seek to exploit the likely significant psychological impact of an attack targeting mass gatherings in large metropolitan areas during the 2010 holiday season, which has symbolic importance to many in the United States," the joint FBI and Homeland Security bulletin said.
Umar Farouk Abdulmutallab is accused of trying to blow up a Northwest Airlines flight from Amsterdam by igniting an explosive in his underwear. Passengers saw flames and subdued Abdulmutallab.
He's due to be arraigned Thursday in federal court in Detroit. Abdulmutallab, who is serving as his own lawyer, is being held at a prison in Milan, Mich., while he awaits trial.
Earlier this month a man was caught in anas he planned to set off a bomb at a crowded Christmas tree lighting ceremony in Portland, Oregon. And in October, al Qaeda's Yemeni offshoot - which also claimed responsibility for the Christmas airliner attack - tried to take down two cargo planes over the U.S. That plot was foiled after officials received a tip, including the packages' tracking numbers, from Saudi Arabian intelligence.
Counterterrorism officials said they could not discount potential threats from other terror groups, such as al Qaeda's offshoots in Iraq and the Islamic Maghreb, Pakistan and Somalia.
"Al Qaeda and other terrorist groups continue to seek innovative ways to conduct attacks and circumvent security procedures, and we remain concerned that the holiday season provides attractive opportunities for terrorists to target the Homeland," the intelligence bulletin said.