Lisbon, Portugal (CNN) -- President Barack Obama stood by new controversial screening measures Saturday, calling methods such as pat-downs and body scans necessary to assure airline safety.
Speaking at a NATO press conference in Lisbon, Portugal, the president called the balance between protecting travelers' rights and their security a "tough situation."
Per the new rules, travelers may be subject to full-body scans at 400 such machines in 69 airports nationwide. Those who voluntarily opt out -- as well as those who set off a scanning machine or a metal detector -- are subject to a pat-down. Some travelers have likened the pat-downs to groping.
The president said such methods are needed after what happened December 25, 2009, when Umar Farouk Abdulmutallab of Nigeria allegedly boarded a flight from Amsterdam to Detroit with a bomb hidden in his underwear. Abdulmutallab reportedly failed to set off the bomb, which metal detectors didn't detect, though his attempt led to airport screening procedures that have caused a holiday travel uproar.
"At this point, the Transportation Security Administration, in consultation with our counterterrorism experts, have indicated to me that the procedures that they've been putting in place are the only ones right now that they consider to be effective against the kind of threat that we saw in the Christmas Day bombing," said Obama.