Umar Farouk

Sept. 11, 2001: Terrorists use commercial airliners to attack World Trade Center towers in New York City and other U.S. sites. Nov. 19, 2001: Federal officials order cockpit doors locked and hardened. Nov. 19, 2001: The Transportation Security Administration is created to oversee security on all modes of transportation. Dec. 22, 2001: Terrorist Richard Reid tries to ignite bombs in his shoes aboard a transatlantic flight, prompting shoe inspections at all U.S. airport security checkpoints.

After concluding that he has taken on an operational role in attempted terrorist attacks, the Obama administration has authorized the capture or killing of a U.S.-born Muslim cleric who is believed to be in Yemen, U.S. officials said. Anwar Awlaki, 38, who was born in New Mexico, recently was added to the CIA target list after a special government review of his activities, prompted by his status as a U.S. citizen, one of the officials said. Awlaki was in e-mail contact with Nidal Malik Hasan, an Army major accused of killing 13 people at Ft. Hood, Texas.

Security and intelligence lapses allowed a suspected terrorist to board a U.S.-bound airliner on Christmas Day, President Obama said from Hawaii today, interrupting his vacation to speak about the failed bombing attempt. "A systemic failure has occurred, and I consider that totally unacceptable," Obama said. The president said he learned in the last 24 hours that information about the suspect, Umar Farouk Abdulmutallab, had been passed to "a component of our U.S. intelligence community" weeks ago, but that the information was not effectively distributed and the Nigerian man was not added to a "no-fly" list.

Reporting from Beirut — Al Qaeda's leader claimed responsibility for the Christmas Day attempt to blow up an American civilian jet in an audio tape broadcast today on Arab television. In the clip, Osama bin Laden said his group was behind the failed attempt by Umar Farouk Abdulmutallab to blow up a Detroit-bound Northwest Airlines flight. Speaking directly to President Obama, he vowed to continue launching terrorist attacks against the United States so long as Washington supported what he described as Israel's unjust treatment of Palestinians.

The federal trial of the so-called underwear bomber came to an abrupt halt on Wednesday when the defendant, Umar Farouk Abdulmutallab, pleaded guilty to charges of trying to blow up an international flight heading for Detroit. Abdulmutallab entered his plea to all eight felony counts before U.S. District Judge Nancy Edmunds, court spokesman Rod Hansen said in a telephone interview. Edmunds set sentencing in the case for Jan. 12. The Nigerian faces a sentence of life in prison on the charges, which include conspiracy to commit an act of terrorism, attempted murder and attempted use of a weapon of mass destruction.

Atty. Gen. Eric H. Holder Jr. and the White House are floating the idea of legislation that would create a new exception to the Miranda rule for suspected terrorists. It's not as outrageous as Sen. Joe Lieberman's proposal that accused terrorists be stripped of their U.S. citizenship, but it's still a bad idea. In a television interview this week, Holder said only that he wanted to work with Congress on legislation to provide investigators with "necessary flexibility." White House Press Secretary Robert Gibbs was equally general in his comments, and the administration hasn't offered a detailed proposal.

Rep. Mike Rogers (R-Mich.), a former FBI agent who has criticized the Obama administration's interrogation policies for terrorism suspects as too restrictive, has been named the next chairman of the House Intelligence Committee. Rogers, who represents Michigan's 8th Congressional District, was appointed to the post by House Speaker-designate John A. Boehner (R- Ohio), who made the announcement Wednesday. Rogers replaces Rep. Peter Hoekstra of Michigan's 2nd District, the ranking Republican on the committee, who is retiring.

A U.S. appeals court rejected a constitutional challenge to the government's use of body-imaging scanners at the nation's airports, ruling that the need to detect hidden explosives outweighs the privacy rights of travelers. The 3-0 decision announced Friday noted that passengers may avoid the scans by opting to undergo a pat-down by a screening agent. But since the body scanners became standard last year, more than 98% of air travelers have chosen to step into a machine, raise their arms and pose for "advanced imaging," the Transportation Security Administration said.

The Tsarnaev brothers were armed with at least three firearms and several improvised bombs - including a pressure-cooker explosive - during confrontations with police, an arsenal that will be traced to determine whether someone outside the U.S. helped the Boston bombing suspects obtain and build the weaponry, a law enforcement official said Saturday. Meanwhile, some investigators said the Boston Marathon bombing did not appear to have been orchestrated by Al Qaeda, several U.S. officials said Saturday.

What does it take to be banned from air travel? U.S. officials are reviewing the watch list and screening procedures, but not all lists are equal: Terrorist Identities Datamart Environment database : This is the largest collection, with about 550,000 people. U.S. intelligence and law enforcement as well as allies can nominate "known or suspected terrorists" for this database. The TIDE list is maintained by the National Counterterrorism Center and was set up after the Sept.