CBS News has more information on the global terrorism alert that has 19 US embassies shuttered, courtesy of former Bush administration national-security adviser Juan Zarate. The plot uncovered by intelligence services is similar to a 2010 plot against Europe that got stymied by its early exposure. In this case, though, the operatives of the current plot have already been dispatched, and may be taking orders from an innovative mastermind in al-Qaeda, who recently resurfaced in Yemen:

CBS News’ Bob Orr reports that according to sources, the intercepted chatter indicates a large scale attack may be imminent and the terrorists involved already have their orders and could be in place.

CBS News security analyst Juan Zarate, former Deputy National Security Adviser to President George W. Bush, told “CBS This Morning,” the plot is “reminiscent of the plot in 2010 … to attack European sites.

“People were worried about Mumbai-style attacks coming from the al Qaeda core,” Zarate said, adding, “It never materialized but officials were worried that they actually had operatives in place. And, that’s a great concern here.”

Zarate also answers the question about Obama administration claims in 2012 of decimating AQ. That only applies to the “core” AQ structure in Pakistan and Afghanistan, but the affiliates are filling the gap:

Zarate said that while Obama Administration has touted their “decapitation” of al Qaeda, this “decimation of al Qaeda” has been focused on “that core, the group in Pakistan and Afghanistan led by bin Laden and [Ayman al] Zawahiri.”

“The problem is you’ve had the rise of the al Qaeda affiliates, groups in Yemen, North Africa, East Africa,” he continued. “Those groups have taken up the strategic and operational mantle for al Qaeda and the group in Yemen has been the most dangerous because they want to hit the United States.”

The US and other Western nations now worry about new methods of deploying suicide bombers, thanks to the return of Ibrahim Hassan al-Asiri. The US had originally thought that Asiri was killed in the same drone strike that killed Anwar al-Awlaki, but Yemen had denied this, and they were clearly correct. Asiri has been credited with creating the notorious underwear bomb that failed to ignite on Christmas Day in 2009 and a similar bomb that worked earlier the same year in an attempt to assassinate a Saudi security chief. The assassin, Asiri’s brother, had the bomb inserted into his rectum, which killed the assassin instantly but failed to kill the target. Last year, Asiri was credited with designing a surgically-implanted bomb that could evade X-rays, although it has yet to be deployed.

The real question isn’t necessarily how to detect the surgically-implanted bomb, which the West has had at least seventeen months to research. It’s what Asiri has designed since that should have them worried.