By Gilbert Kreijger

THE HAGUE (Reuters) - The Netherlands and Nigeria said on Wednesday they would use full-body scanners at airports after a failed Christmas Day attack on a U.S.-bound plane by a 23-year-old Nigerian suspect who passed through both countries.

Amsterdam's Schiphol Airport will begin using the scanners -- which "see" through clothing -- within three weeks to check people traveling to the United States, after consultations with U.S. authorities, the Dutch interior minister said.

Nigeria will equip its international airports with the scanners in the New Year, an aviation official said.

In the United States, the botched attack aboard the Detroit-bound U.S. airliner has prompted congressional calls for greater use of body scanners that advocates say would have detected non-metallic items like explosives smuggled aboard.

The attack exposed what President Barack Obama on Tuesday called "human and systemic failures" in U.S. security agencies, and spurred speculation that U.S. intelligence chief Admiral Dennis Blair or Homeland Security Secretary Janet Napolitano could be forced to resign.

The White House was standing by the two officials, saying Blair and Napolitano had the president's support. "This is not about one person or one agency," said White House spokesman Robert Gibbs.

Although the Christmas Day attack was on an inbound U.S. flight where security checks abroad are critical, the September 11 2001, attacks all involved hijackers on internal U.S. flights.

Current use of whole-body scanners is limited to 19 U.S. airports and is optional, with pat-downs an alternative.

Full-body scanners, unlike the standard archway metal detectors currently used in airports around the world, use radio waves to generate a picture of the body that can see through a person's clothing and spot hidden weapons or packages.

COST AND PRIVACY CONCERNS

Concerns over cost and privacy have so far hindered the widespread use of the technology, with critics arguing it is unacceptably intrusive.

Dutch Interior Minister Guusje ter Horst said standard procedures were followed properly in the case of Umar Farouk Abdulmutallab, the Nigerian accused of trying to blow up the flight from Schiphol to Detroit on Christmas Day.

"We will make these (scanning) machines, about 15 in total, available for flights to the United States within three weeks' time," ter Horst told a news conference in The Hague.

But since Schiphol has twice as many gates for U.S. departures as scanners, not all flights will be covered by the new machines. Passengers on flights not subject to the new scanners will instead receive thorough pat-downs.