Midair Bomb Attempt Fails

A passenger on a Detroit-bound Northwest Airlines flight tried Friday to detonate an explosive device strapped to his leg and later told investigators he had affiliations with Al Qaeda and was trying to blow up the plane, according to a senior U.S. official.

"We believe this was an attempted act of terrorism," said a White House official.

The suspect told investigators he was given the device by al Qaeda operatives in Yemen, along with detonation instructions, the official said. "This guy claims he is tied to al Qaeda, specifically in Yemen," the official said. "He claims he was on orders from al Qaeda in Yemen. Who knows if that's true?"

Rep. Peter King (R., N.Y.) identified the man as a 23-year-old Nigerian named Abdul Mudallad. Mr. King said the flight began in Nigeria and went through Amsterdam en route to Detroit. The suspect's name didn't appear on any terrorist watch lists maintained by U.S. authorities, he said, but it turned up "hot" in other terrorism-related databases maintained by intelligence officials.

One U.S. intelligence official said the alleged explosive was a mix of powder and liquid. Mr. King said the concoction was strapped to Mr. Mudallad's leg.

The White House said President Barack Obama, vacationing in Hawaii, was notified of the incident after 9 a.m. local time and held two secure conference calls with his national-security team. He ordered increased security for air travel, the White House said. The Department of Homeland Security said airline passengers should expect to see additional screening measures on both domestic and international flights.

The incident aboard Northwest Flight 253, an Airbus 330-300 carrying about 278 passengers, came as the plane was approaching the airport just before noon. It landed safely after the pilots declared an emergency. Though a Northwest flight, the plane had Delta markings. After a merger, Delta Air Lines Inc. now owns Northwest.

Stephanie van Herk, a passenger from the Netherlands who was in seat 18B, said the plane had lowered its landing gear when she heard a loud bang. At first she thought the plane might have blown a tire, she said, but then she saw flame leap from the lap of a man in the row behind her in the window seat 19A. "It was higher than the seat," said Ms. van Herk, 22 years old.

"Then everyone started screaming," she said. "It was panic." Flight attendants shouted "What are you doing? What are you doing?" They called for water, and the man began pulling down his burning pants, said Ms. van Herk. She and other passengers got water from the galley and the man was doused. Then a Dutch man jumped him.

Flight passenger Syed Jafry, a U.S. citizen who had flown from the United Arab Emirates, said he was seated three rows behind when he saw a glow and smelled smoke. He said, "A young man behind me jumped on him."

The explosive was at first believed to have been a small firecracker.

One passenger was taken to the University of Michigan Medical Center and remained hospitalized Friday.

Shortly after the plane landed around 11:50 a.m. Detroit time, the Transportation Security Administration said that "out of an abundance of caution," the jet's passengers were put through a special security screening and luggage was re-examined. TSA and FBI officials interviewed passengers as the plane sat at a remote corner of the airport, surrounded by law-enforcement and emergency vehicles.

Regardless of what the investigation uncovers about the suspect's motives or the material that ignited, Friday's incident is likely to renew debate over whether new security systems are necessary to allow flight attendants to alert cockpit crews.

In addition to calling pilots on the intercom, airlines and security experts for years have debated the idea of providing cabin crews with additional ways to warn pilots about potential threats from passengers. Video cameras, wireless alerting devices or some type of discreet alarm switch have all been discussed as remedies.

The incident also is bound to renew debate over the effectiveness of the current system of international "no-fly" lists, aimed at identifying passengers with terrorist connections and keeping them off airliners around the globe.

So far, the Federal Aviation Administration and many airlines have been resisting such mandates, arguing they are expensive and unnecessary.

The additional security measures ordered by TSA, according to government and industry officials, could cause further delays to what already has been a difficult and storm-battered holiday travel season for millions of U.S. passengers

Delta Air Lines Inc. said it was cooperating with investigators.

—Cam Simpson and Alex P. Kellogg contributed to this article.
WSJ