"You can basically hit or heat it," says Neil Gibson, an explosives expert. "It's unlike other substances that break down or are more volatile."
European security officials say al-Qaida in the Arabian Peninsula is determined to target U.S.-bound airliners — but not necessarily flights inside Europe.
"At this point, the likelihood of an overseas attack in Europe from al-Qaida seems less likely than other scenarios," says a European security official, who spoke on condition of anonymity because of the sensitivity of his job. "But they definitely have the intent for all sorts of attacks and it appears their capability is increasing."
The Olympic torch arrives in Britain next week with a controversy already raging over U.K. border security.
Staff shortages, poor planning and a fear of racial profiling are being blamed for chaos at some of the country's busiest airports, according to John Vine, the independent chief inspector of borders and immigration who issued a damning report on the problems Thursday.
Britain's government has previously acknowledged that security equipment at airports is only about 60 percent effective in detecting potentially hazardous items.
Still, the investment in Olympics security has been massive. Troops, armed police, warships and air-to-surface missiles will all be on standby to protect the public.
Security officials are planning for an array of potential nightmares during the games — a water-based offensive from the Thames, an airline attack using a hidden bomb or a homegrown attack like the 2005 suicide bombings that killed 52 people during London's busy rush hour.
One of their biggest fears, however, is a lone-wolf terrorist who stays off the radar until he strikes.
Other possibilities exist, too, such as a remote-controlled aircraft carrying deadly poison, according to British military Lt. Col. Brian Fahy, responsible for community relations during the London Games.
While Rapiscan, based in Torrance, Calif., is a key security partner for the Olympics, its full-body advanced scanners won't be used at the games.
"We are providing all of the X-ray and security equipment, but body scanning is not part of this," says Kant, the Rapiscan executive. "We know — we believe — the amount of security and the level of security being provided is very high. I think more than just the Olympics, what the Yemen plot has shown us is that the plot is very real — there are known gaps — and it needs to be taken into account."
ASK THE EXPERTS
It may not be polite or politically correct but it works, say the Israelis.
The grilling of passengers boarding planes bound for Israel begins at the airport with a litany of security questions. After that, it's not unusual to have a body search in a private room and an equipment search. It goes without saying most passengers are scanned before they get on the plane.
But the process doesn't necessarily stop at departures.
Sometimes upon landing, passengers are herded into rooms where their liquids are squirted out, computers disassembled and batteries removed. And Israeli security agents make no apologies for profiling.
"The system knows about a suspect long before they arrive at the airport, which is something that doesn't happen at many airports around the world," says a senior Israeli airport security official, speaking on condition of anonymity because of security protocol.
"The cons in this are that it breaches people's privacy to a certain extent and also the system costs a lot of money to run."
Associated Press writers Angela Charlton in Paris, Ian Deitch in Jerusalem, David Stringer in London and Slobodan Lekic in Brussels contributed to this report.
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