The United States is increasingly concerned about the threat posed by Al-Qaeda's network in Yemen and is moving to pile pressure on the militants, a US counter-terrorism official said on Wednesday.
While Al-Qaeda's leadership based in Pakistan had suffered serious setbacks, its affiliates in Yemen had regrouped and emerged as a "virulent" danger, the official, who spoke on condition of anonymity, told AFP.
"They're not feeling the same kind of heat -- not yet, anyway -- as their friends in the tribal areas" of Pakistan, he said.
"And everyone involved on our side understands that has to change."
The official did not specify how the United States would counter militants in Yemen but in Pakistan, the Central Intelligence Agency has targeted Al-Qaeda and Taliban figures with a major bombing campaign using unmanned aircraft.
The Wall Street Journal and the Washington Post reported Wednesday that the new assessment of the threat raised the prospect of expanded US operations in Yemen, including CIA drone strikes.
Asked about the revised assessment of the threat in Yemen and possible stepped up US operations, CIA spokesman George Little said: "This agency and our government as a whole work against al-Qaeda and its violent allies, wherever they appear."
A US effort to counter militants in Yemen has been led mostly by the US military, but some inside the administration have proposed a larger role for the CIA, similar to the drone strikes in Pakistan, the Journal wrote, citing unnamed officials.
The US counter-terrorism official said the administration would take a "tailored approach" to Yemen and that it was not a case of choosing intelligence agencies over the military.
"When it comes to who carries out that policy, it's not a zero-sum game or a question of this organization or that. You have to combine and apply the tools and tactics that make the most sense, given the specific situation," the official said.
"Yemen isn't Pakistan, and the United States in any case takes a tailored approach."
The CIA and the US military's special operations forces have deployed surveillance equipment, robotic aircraft and personnel in Yemen, Djibouti, Kenya and Ethiopia to target Al-Qaeda's network in Yemen as well as Islamist militants in Somalia's Shebab movement, the Journal reported.
US officials believe Al-Qaeda in Yemen and Shebab in Somalia have forged stronger links and are increasing cooperation, the paper said.