• Clinton: Terrorists seek 'more perverse,' 'terrible' ways to kill innocents

    An alleged al-Qaida plot to blow up an underwear bomb aboard a jet headed to the U.S. was stopped by the CIA before it could be launched. NBC's Pete Williams reports.

    By NBC News

    Secretary of State Hillary Rodham Clinton told reporters Tuesday that terrorists keep trying to come up with “more and more perverse and terrible ways to kill innocent people” after a plot by al-Qaida's affiliate in Yemen to bomb a U.S.-bound airliner was foiled by the CIA.

    U.S. officials said Monday that the plot involved a bomb that improved on the one that had been sewn into the underpants of Umar Farouk Abdulmutallab, who failed in a plot to blow up a Detroit-bound airliner on Christmas Day 2009.

    The latest bomb had a more refined detonation mechanism and was "totally non-metallic," which officials told NBC News would have made it more difficult to detect by traditional screening processes.

    Michael Leiter, former director of the National Counterterrorism Center, talks to TODAY's Ann Curry about al-Qaida's failed plan to bomb an airliner headed to the U.S. and what the foiled plot tells us about the current state of al-Qaida.

    “With respect to the plot that was discussed in Washington, as the White House said, the device did not appear to pose a threat to the public air service, but the plot itself indicates that these terrorists keep trying,” Clinton, who is in New Delhi, India, said.

    “They keep trying to devise more and more perverse and terrible ways to kill innocent people, and it's a reminder as to why we have to remain vigilant at home and abroad … protecting our nation and protecting friendly nations and peoples like India and others,” she added.

    John Brennan, President Obama's chief counterterrorism adviser, talks to TODAY's Ann Curry about al-Qaida's failed plan to bomb an airliner headed to the U.S. and says the would-be bomber is "no longer a threat to the American public."

    Clinton also called for India’s neighbor Pakistan “to do more” to tackle terrorists. “It needs to make sure that its territory is not used as a launching pad for terrorist attacks anywhere, including inside of Pakistan, because the great unfortunate fact is that terrorists in Pakistan have killed more than 30,000 Pakistanis,” she said.

    CIA foiled al-Qaida plot to destroy US-bound airliner

    The new underwear bomb had some “refinements on reliability” that made it more likely to explode, a U.S. counterterrorism official told NBC News. In addition to being a threat to commercial planes, this type of bomb could be used in crowded places, on other transportation systems or for assassinations, the official said.

    More than 30 Yemeni troops killed in militant attack

    The official noted that the bomb “was never near a plane” and “never posed a risk.” The plot was disrupted well before it threatened Americans or U.S. allies, the official added.

    Reports: Al-Qaida leader wanted in USS Cole bombing killed in Yemen airstrike

    The U.S. received the device last month. The FBI is conducting technical and forensic analyses on it.

    The official would not specify which international security service provided the intelligence that led to the unraveling of the plot, as there is concern about retaliatory attacks against U.S. targets inside Yemen.

    Bin Laden in hiding: Hatching horrific plots despite crippling attacks on al-Qaida

    The FBI said in a statement that the successful operation was the "result of close cooperation with our security and intelligence partners overseas."

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