Al-Qaeda in the Arabian Peninsula (AQAP) and one of its leading figures — American-born Muslim cleric Anwar Al-Awlaki — have increasingly become priority US targets since the group took responsibility for a failed plot to blow up a US passenger jet on Christmas Day.
Awlaki has also been tied to an Army psychiatrist charged with killing 13 soldiers in a November 2009 shooting rampage at Fort Hood, Texas.
"They're not feeling the same kind of heat — not yet, anyway — as their friends in the tribal areas. And everyone involved on our side understands that has to change," a US counter-terrorism official said.
Admiral Mike Mullen, who as chairman of the Joint Chiefs of Staff is the top US military officer, acknowledged on Wednesday that while Al-Qaeda in Pakistan had suffered setbacks, its affiliates in Yemen and North Africa had become "more robust" in recent years.
Still, US officials stressed that increased attention to Al-Qaeda in Yemen did not mean less concern about Al-Qaeda in Pakistan, described by military and intelligence officials as the core of Al-Qaeda operations.
"They remain extremely dangerous and they are still the hub to all the spokes, the heart of Al-Qaeda," the US official said, speaking on condition of anonymity. "No one's even close to saying it's over in Pakistan - not at all. In fact, we not only have to keep up the pressure there, we have to spread it to Al-Qaeda's nodes and affiliates elsewhere."
US military and spy agencies have already been stepping up intelligence gathering using surveillance aircraft, satellites and signals intercepts to track Al-Qaeda targets in and around their bases in Yemen.
Increased intelligence could help carry out a targeted killing program in Yemen, following what US officials see as a successful CIA-run program using pilotless drone aircraft in Pakistan.
Washington is considering all options in Yemen, including drawing from experiences in Pakistan, officials say.
The CIA did not comment on specifics of any of its programs in Yemen or elsewhere.
"This agency and our government as a whole work against Al-Qaeda and its violent allies, wherever they appear," said CIA spokesman George Little.
