Schuringa said someone started yelling: "Fire! Fire!" Then there was smoke. That's when Schuringa said he knew something was terribly wrong. When he noticed that Abdulmutallab was not moving, he grew suspect. He jumped over the passenger next to him and lunged over Abdulmutallab's seat. Schuringa said he saw that Abdulmutallab had his pants open and he was holding a burning object between his legs. "I pulled the object from him and tried to extinguish the fire with my hands and threw it away," Schuringa said.

Some airlines were telling passengers on Saturday that new government security regulations prohibit them from leaving their seats beginning an hour before landing
The regulations are a response to a suspected terrorism incident on Christmas Day.
Air Canada said in a statement that new rules imposed by the Transportation Security Administration limit on-board activities by passengers and crew in U.S. airspace. The airline said that during the final hour of flight passengers must remain seated. They won't be allowed access to carryon baggage or to have any items on their laps.

Flight attendants on some domestic flights are informing passengers of similar rules. Passengers on a flight from New York to Tampa Saturday morning were also told they must remain in their seats and couldn't have items in their laps, including laptops and pillows. The TSA issued a security directive for U.S.-bound flights from overseas, according to a transportation security official who spoke on condition of anonymity because the official was not authorized to speak publicly.

The official said passengers traveling internationally could see increased security screening at gates and when they check their bags, as well as additional measures on flights such as stowing carryons and personal items before the plane lands. Homeland Security Secretary Janet Napolitano said in a statement Saturday that passengers flying to the U.S. from overseas may notice extra security, but she said the measures "are designed to be unpredictable, so passengers should not expect to see the same thing everywhere."

A Nigerian passenger on a Northwest Airlines flight from Amsterdam allegedly attempted to start a fire as the plane prepared to land in Detroit on Friday, according to authorities. The incident has sparked a major international terrorism investigation. Air Canada said it was limiting passengers to one carryon bag in response to a request from the U.S. and Canadian governments. The airline advised U.S.-bound passengers to restrict their carryon item to "the absolute minimum" or to not carry any bag on board at all. "Carriage of any carryon item will result in lengthy security delays for the customer," the airline said.

U.S.-bound flights on all airlines are experiencing significant delays, said Duncan Dee, Air Canada's executive vice president and chief operating officer. A spokeswoman with Infraero, a Brazilian government agency that oversees airport infrastructure, said that airlines had been asked by federal authorities to add another layer of security for international flights originating in the country after the attempted attack in the U.S. The official, who spoke on condition of anonymity because she was not authorized to discuss the matter, said that passengers would face an extra screening that would take place just before they boarded planes. She would give no more details, citing security concerns.

David Castelveter, a spokesman for the Air Transport Association, said the domestic airline industry has been in close coordination with the security administration since Friday's incident and there will be increased scrutiny of passengers. He declined to comment on whether new regulations have been put in place.

A Michigan man who was aboard Northwest Airlines Flight 253 says he witnessed Umar Farouk Abdul Mutallab trying to board the plane in Amsterdam without a passport. Kurt Haskell of Newport, Mich., who posted an earlier comment about his experience, talked exclusively with MLive.com and confirmed he was on the flight by sending a picture of his boarding pass. He and his wife, Lori, were returning from a safari in Uganda when they boarded the NWA flight on Friday.

More details have also emerged of what happened on flight 253 prior to landing at Detroit. Abdulmutallab went to the bathroom for about 20 minutes. When he returned, he said his stomach was upset and pulled a blanket over himself. The 278 passengers on the eight-hour Delta Airways flight from Amsterdam were first alerted that something was wrong when they heard what was described as "a firecracker in a pillowcase".

One passenger, Jasper Schuringa, who was the first on the plane to tackle and subdue the suspect, told CNN: "I basically reacted directly. when you hear a pop on the plane, you are awake. I just jumped. I didn't think, I just went over there and tried to save the plane – and we did."

Mr Schuringa, who had burns to one of his hands, added: "A fire started under his seat. I was calling for water, water. But then the fire was getting a little worse. So I grabbed the suspect out of the seat, because, if there was any more explosives on him, that would have been very dangerous. And then the flight attendants came. We took him to first class and stripped him to make sure he had no more weapons on him. "It was very quick. Everyone was panicking," he said of the scene on the descending aircraft.

The other disturbing development, she added, is the use of the body to conceal explosives. In August a terrorist tried to assassinate the Saudi Prince Mohammed bin Nayef with explosives implanted in his body.

"The bomber suffered third-degree burns on his leg," Dr Leivesley said. "It's possible that a part of the explosive was hidden either inside the inner thigh or wrapped over that area with skins. With baggy clothing, it could be missed during a search, as could a syringe hidden in the groin. There are no metal components involved, so it wouldn't trigger a security device. He would then use the syringe to inject a liquid which would detonate the explosive."

Another significant factor is the report that the bomber was an engineering student at University College London. Dr Leivesley said that al-Qa'ida was recruiting people with engineering qualifications as well as highly placed scientists, particularly in the nuclear field.

"Al-Qa'ida is finding it difficult to recruit young people," she said. "And, interestingly, the election of Barack Obama is a factor in that, because, whatever you think of him as a president, the fact of him shows young people that there is an alternative to killing yourself. Al-Qa'ida is, however, targeting more highly skilled people."