LAGOS, Nigeria (AP) — Body scanners bought for Nigeria's international airports in the wake of a Christmas Day bomb attempt remain unused months later, though officials said Wednesday that U.S. air marshals now protect flights coming into the West African nation.

Harold Demuren, director general of the Nigerian Civil Aviation Authority, said that the government still needs to train officers to man the screening devices already in place at Lagos' Murtala Muhammed International Airport and at the international airport in Abuja. The machines have yet to be installed at the international airports in Kano and Port Harcourt, he said.

However, Demuren said explosive detection equipment already being used and full body pat-downs for international passengers will make sure a similar attack "never happens again."

"We want to make our airports extremely unfriendly to terrorists," Demuren said at a U.S. Embassy-sponsored press conference.

The Nigerian government purchased 10 body scanners immediately after Umar Farouk Abdulmutallab allegedly attempted to bring down a Detroit-bound airliner with an explosive device hidden underneath his clothes. Abdulmutallab started his journey at Murtala Muhammed International Airport and only went through a metal detector before boarding his initial flight.

Security officials suggest that body scanners, which create detailed 3-D images of passengers' figures, would have shown the explosives that prosecutors say Abdulmutallab hid inside his underwear. However, that equipment now sits idle as international passengers walk through security screening at Murtala Muhammed, the oil-rich nation's busiest airport.

The U.S. gave Nigeria four full-body scanners for its international airports in 2008 to detect explosives and drugs. Those machines remain in use by federal anti-drug agents at the Lagos international airport and elsewhere, though Abdulmutallab did not undergo a screening.

Since the bombing attempt, relations soured between the U.S. and Nigeria, one of the country's biggest suppliers of crude oil. The U.S. initially put Nigeria a list of "countries of interest" that included Afghanistan, Cuba, Iran and Libya, requiring incoming passengers to undergo additional screenings. That sparked a nationalist outcry in Nigeria that only calmed after the U.S. eased the restrictions.

The bombing attempt did, however, push Nigeria into signing an agreement allowing air marshals aboard international flights between the U.S. and Africa's most populous nation. U.S. Ambassador Robin Renee Sanders told reporters Wednesday that the air marshal program to Nigeria began several months ago, but declined to elaborate.

Two direct flights now leave Lagos for the U.S.: a Delta Air Lines Inc. flight to Hartsfield-Jackson Atlanta International Airport and Nigerian carrier Arik Air's flight to New York's John F. Kennedy International Airport. Continental Airlines Inc. plans to launch new daily nonstop flights between Houston and Lagos late next year.

Nigeria's aviation history remains marred with air fatalities and lax security. The U.S. put a six-year ban on direct flights from Murtala Muhammed International Airport in the 1990s over security concerns. Even today, some passengers encounter officials at the airport who try to solicit cash bribes while baggage handlers rifle through luggage for valuables.

In October 2005, an airplane flown by Nigerian carrier Bellview Airlines crashed after takeoff from Lagos, killing all 117 people onboard. In May 2002, an EAS Airlines jet plowed into a heavily populated neighborhood after taking off from Kano, killing 154 people in the plane and on the ground.

Since the crashes, Nigeria has worked with the U.S. Federal Aviation Administration to improve its safety ratings. While not yet considered in the top echelon on international airports, Demuren promised the country would continue to improve with assistance from the U.S.

"It's establishing a safety culture on a solid rock," he said.