U.S. drones strike another body blow to al Qaeda

An American drone aircraft has killed another top al Qaeda operative in Pakistan. Abu Hafs al-Shahri, the terror group's chief of operations in Pakistan, was killed earlier this week.

CIA drone strikes made headlines from time to time, but they've been going on for years. It turns out, Osama bin Laden's al Qaeda has been severely crippled by them.

CBS News correspondent Bob Orr reports that the loss of al-Shahri is another body blow for al Qaeda's core.

In the past four months, at least three other senior terror leaders have been killed: Atiyah al Rahman, al Qaeda's most recent No. 2; Ilyas Kashmiri, a senior commander charged with planning foreign attacks; and Fazul Mohammed, one of the key operatives behind the 1998 bombings of two U.S. embassies in Africa.

Earlier this month, senior leader al Qaeda leader Younis al Mauritani was captured in Pakistan.

All of these losses have occurred after bin Laden was killed on May 1.

Michael Leiter, who until July headed the National Counterrorism Center, says al Qaeda, now run by Ayman al Zawahiri, is critically wounded, but "there's nothing static about counterterrorism."

"Really, the ranks of al Qaeda in Pakistan have been very seriously thinned. So, I think they could still pull off an attack, but I think it is much less likely that they could pull off a catastrophic attack like 9/11," Leiter says.

Beyond losing operatives, al Qaeda is also losing some popular support.

"Over time, al Qaeda's message is resonating less and less. Al Qaeda's methods of attack, suicide bombings against innocents, (are) becoming less and less popular," Leiter says.

But, the bin Laden network is not dead and we were reminded of that just last week, when overseas intelligence picked up a tip of a possible attack around the 10th anniversary of 9/11. U.S. officials still cannot dismiss that threat.

The greater danger, though, may now come from al Qaeda franchises across Africa and the Gulf region. There are threats from Somalia, where nearly 50 Americans have joined the fighters of al Shabaab. There's also a threat in Yemen, home to al Qaeda in Arabian Peninsula. AQAP has tried twice in two years to hit the US: First with the underwear bomb and later with explosives hidden in printers.

"They are innovative and they are trying to move things quickly and that certainly does pose a challenge to the United States and our allies," Leiter says.

The U.S. has not yet brought the same pressure on AQAP as it has on al Qaeda, but, going forward the Yemen group will likely be the top target.