( CNN ) -- The infiltration of a Middle Eastern terror network by a mole who helped foil a plot to blow up a U.S.-bound plane was a `` phenomenal , '' `` brilliant '' and `` powerful '' success , experts said Wednesday . It 's unclear how much of the credit should go to the United States or to Saudi Arabia , for whom sources say the mole was working , but both countries have delivered a practical and psychological setback to al Qaeda in the Arabian Peninsula , analysts on the region said . Western officials describe that affiliate as al Qaeda 's most dangerous . `` It 's a devastating blow to al Qaeda , though not a fatal one , '' said Juan Zarate , who was deputy national security adviser for combating terrorism under President George W. Bush . `` What this demonstrates is that we have the ability to get on the inside . '' And the plot , by the same group that launched a failed attempt to bomb a U.S.-bound airliner on Christmas 2009 , demonstrates the continued `` rise of the affiliates , '' he said . `` We have a decimated al Qaeda core -- the al Qaeda of 2001 that we have battled and really dismantled in many ways has metastasized and is now presenting itself in this regional form . '' This latest intelligence success marks the deepest known penetration into al Qaeda , said Ali Soufan , a former FBI official who oversaw highly sensitive international terrorism cases . But he noted many intelligence efforts remain secret . `` It 's a major success for the CIA and for the intelligence community , '' he said . And , he noted , as in this case with Saudi Arabia , `` overseas most of our work is done in cooperation with friendly services . '' Of the al Qaeda affiliate groups trying to carry out terrorist operations today , al Qaeda in the Arabian Peninsula is the closest version to the network Osama bin Laden led , Soufan said . Bruce Riedel , who spent 30 years in the CIA and was a senior adviser on the Middle East to four presidents , said thwarting the bomb plot is `` primarily a Saudi success story '' -- and not their first . `` They foiled the AQAP plot in October 2010 to send bombs to the U.S. on FedEx and UPS planes , '' he noted . That plot was foiled by an informant . Some details remain unknown . This time , Riedel said , Saudi intelligence managed to `` get access to AQAP 's plot and actually get the bomb . '' Still , thwarting this attack does n't damage the organization substantially in the big picture , analysts said . `` While this is a good technical success , the harsh reality is that in Yemen , al Qaeda in the Arabian Peninsula is growing , getting more powerful , recruiting more assets and taking advantage of the fact that Yemen is essentially the Humpty Dumpty of the Arabian Peninsula -- it 's falling apart , broken , '' said Riedel , now a senior fellow at the Brookings Institution . CNN terrorism analyst Paul Cruickshank added that while it is a `` big intelligence success '' for the United States and Saudi Arabia , `` there 's a limit to their success as well . '' The operation did not lead intelligence services to Ibrahim al-Asiri , the chief bomb maker for al Qaeda in the Arabian Peninsula , or to the location where he makes the bombs . `` They were able to take out Fahd al-Quso , who 's a senior operational planner in the group , but they were not able to take out this very dangerous bomb maker who 's ingenious at making bombs , '' Cruickshank noted . Information from the mole led to a CIA drone strike Sunday in Yemen that killed al-Quso , 37 , a senior operative of the al Qaeda affiliate . He was a suspect in the 2000 bombing of the USS Cole in Yemen . He was convicted in a Yemeni court but escaped from jail . All the analysts who spoke to CNN expressed concern that a mole 's involvement was leaked to the media . `` I think authorities , particularly the CIA , would rather not talk about this right now , '' said Zarate , now a senior adviser on counterterrorism for the Center for Strategic and International Studies . These kinds of sources `` can lead to additional counterterrorism successes or insights , '' he said . `` So the fact that this is now front page news certainly does n't help . '' Soufan , who runs a consultancy group on security issues , said , `` When you 're doing operations like this , you have to do whatever you can do to protect sources and methods -- not only of the CIA but also of the other intelligence services that were involved in this . Because down the road they will be hesitant to cooperate with us . '' However , Zarate said , there may be a bit of a silver lining in the leak . `` I think what this will do is it will increase the amount of vigilance and mistrust within al Qaeda circles to outsiders . They need outsiders to supplement their ranks and allow them to plot against the West . ... It will create layers of distrust and will create inefficiencies , '' Zarate said .
Analyst : The intelligence gathered on bomb plot ##ters ` ` the ability to get on the ground '' It 's ` ` primarily a Saudi Arabian story , '' another expert says . Operation did not lead to the terrorist group 's chief bomb maker , one analyst says . The fact that a mole was involved could damage intelligence efforts , experts say .