The millimeter-wave body scanners will be in place in about three weeks, Dutch Interior Minister Guusje ter Horst told a news conference at The Hague.

"We've escaped a very serious attack with serious consequences, but unfortunately in this world there are individuals who do not shy away from attacks on innocent people," she said.

Nigerian suspect Umar Farouk AbdulMutallab, 23, is accused of trying to blow up a Northwest Airlines plane going from Amsterdam to Detroit, Michigan, with explosives that had been concealed in his underwear. He is charged with attempting to destroy an aircraft.

The militant group al Qaeda in the Arabian Peninsula has claimed responsibility for the December 25 plot.

Dutch authorities have already said they were confident in the security measures that were carried out when AbdulMutallab transferred to the Detroit flight from an earlier flight from Nigeria.

The measures they had in place were metal detectors and X-ray machines, however -- and ter Horst admitted they could not have picked up the explosive material that AbdulMutallab was allegedly carrying.

"The introduction of these body scanners would certainly have helped in detecting that he was carrying something on his body," she said. "We know that metal detection does not help to detect non-metal explosives, and these millimeter-wave scanners can do this, which would mean that this would be an improvement."

One passenger on same plane as AbdulMutallab told CNN's "Larry King Live" that the security checks at Schiphol were not as stringent as those she is used to in the United States.

"We walked through and did not have to take our shoes off," said Wisconsin native Richelle Keepman. "Also, my mother had a water bottle in her bag that she'd completely forgotten about. And it went right through and we didn't realize it until we were on the plane."

Ter Horst acknowledged that the systems currently in place are "not watertight," which is why the body scanners are being introduced.

As to privacy concerns -- namely that the scanners could pick up private features of a person's body -- ter Horst said the scan results would first go through a computer, which would then flag any suspicious items to a human.

The scanners will be permanent at Schiphol, and any passengers bound for the United States who do not go through them will be bodysearched, ter Horst said.

Erik Akerboom, the Dutch national coordinator for counterterrorism, said part of the investigation is looking at whether the explosives were brought into Schiphol by someone else, for AbdulMutallab to pick up later.

Dutch authorities are also looking into who he was in touch with while at Schiphol awaiting his connecting flight. They are combing surveillance camera footage from the connections hall, Akerboom said.

AbdulMutallab was traveling on an Italian passport, Akerboom said, without elaborating.

Asked about reports that AbdulMutallab paid for his ticket in cash and was flying only with hand luggage, Akerboom said neither would have necessarily raised any alarms.

"There are several travelers who do this," he said.

AbdulMutallab's name had come to the attention of U.S. authorities before the attack, sources have told CNN in recent days.

His father talked twice about his son's extremist views with at least one CIA representative at the U.S. Embassy in Nigeria and a report was prepared, but the report was not circulated outside the agency, a reliable source told CNN's Jeanne Meserve on Tuesday.

Had that critical information been shared, the man might have been denied passage on the flight, the source said.

A U.S. intelligence official said AbdulMutallab's name, passport number and possible connection to extremists were indeed disseminated. But the official added, "I'm not aware of a magic piece of intelligence -- somehow withheld -- that would have put AbdulMutallab on the no-fly list."

CIA spokesman George Little defended the agency's actions regarding AbdulMutallab, but also said the agency is reviewing data to ascertain whether more could have been done.

State Department spokesman Ian Kelly said department staff did what they were supposed to by sending a cable to the National Counterterrorism Center in Washington about the matter. Kelly said any decision to have revoked the suspect's visa would have been an interagency decision.