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Usama bin Laden dethroned as top terrorist threat to the United States?

That's the assessment of Michael Leiter, head of the National Counterterrorism Center, who testified Wednesday before the House Homeland Security Committee at a hearing on Islamic extremism.

The committee's new chairman, Republican Rep. Peter King of New York, cut right to the chase, asking which Al Qaeda leader poses the greatest threat to U.S. national security.

“Would you say that (Anwar) al-Awlaki is at least as severe a threat today as Bin Laden?” King asked.

“I actually consider Al-Qaeda in the Arabian Peninsula with Al-Awlaki as a leader within that organization probably the most significant risk to the U.S. homeland,” Leiter responded.

Awlaki, a U.S.-born radical cleric, has been on the national security radar for nearly a year and is the first American on the CIA’s kill or capture list. Now believed to be hiding in Yemen, Awlaki is part of the new breed of digital jihadists who use the Internet to inspire their followers to launch lone-wolf or small-cell attacks that are nearly impossible for law enforcement to prevent.

Asked if Awlaki is one of the most successful as far as radicalizing through the Internet, Leiter did not hesitate: “I think Al-Awlaki is probably -- certainly is the most well-known English-speaking ideologue who is speaking directly to folks here in the homeland.”

The committee was told that there are three threat streams: Bin Laden and Al Qaeda senior leadership in Pakistan; affiliated groups in Yemen, Somalia and North Africa, as well as homegrown plots.

“The threat continues to evolve," Homeland Security Secretary Janet Napolitano said. "And in some ways, the threat today may be at its most heightened state since the attacks nearly 10 years ago”

Napolitano was also asked to explain the change in tone from her first appearance before the committee two years ago.

“I pointed out the fact that you do not use the word 'terrorist' or 'terrorism' even once," King said. “In today's statement, you used it more than 60 times. Is it a reflection of the changing emphasis within the administration?”

Napolitano responded. “Well, I think my initial statement before the -- the committee was one of several speeches, and it just happened to be the one that didn't use the word terrorism." She added that she spends the bulk of her time working on counterterror-related activities.

Also of note was Leiter’s statement about the Fort Hood shooting. The alleged shooter Maj. Nidal Hasan exchanged at least 18 e-mails with Awlaki. Leiter said the shooting that left 13 dead and 32 others injured fit the definition of terrorism – a politically motivated act of violence.

“Within about 48 hours of that attack, we designated that a terrorist attack in what we call the worldwide incident tracking system. So from our perspective, it was -- as soon as we had the initial indication of the motivation, we counted it as a terrorist attack," Leiter said. "It can always change back; in this case, it hasn't. “

While the NCTC identified the shooting as an act of terrorism, it was not until Jan. 15, during a background briefing with reporters, that a senior administration official labeled Fort Hood a terrorist plot.