Washington, Aug 25 (IANS): The US Central Intelligence Agency (CIA) now sees one of Al Qaeda's off-shoots - rather than the core group now based in Pakistan - as the most urgent threat to US security, according to the Washington Post.

The new assessment of Al Qaeda's affiliate in Yemen has helped prompt senior Obama administration officials to call for an escalation of US operations there, including a proposal to add armed CIA drones to a clandestine campaign of US military strikes, the influential US daily said Wednesday citing unnamed officials.

The officials cited by the Post, however, stressed that that analysts continue to see Al Qaeda and its allies in the tribal areas of Pakistan as supremely dangerous adversaries.

The officials, it said, insisted there would be no letup in their pursuit of Osama bin Laden and other senior figures thought to be hiding in Pakistan.

Indeed, officials cited by the Post said it was largely because Al Qaeda has been decimated by Predator strikes in Pakistan that the franchise in Yemen has emerged as a more potent threat.

US officials said the administration's plans to escalate operations in Yemen reflect two aims: improving US intelligence in Yemen and adding new options for carrying out strikes when a target is found.

The CIA has roughly 10 times more people and resources in Pakistan than it does in Yemen. There is no plan to scale back in Pakistan, but officials cited by the Post said the gap is expected to shrink.

Proponents of expanding the CIA's role argue that years of flying armed drones over Pakistan have given the agency expertise in identifying targets and delivering pinpoint strikes. The agency's attacks also leave fewer tell-tale signs.

Some government intelligence analysts outside the CIA, however, argued that it would be wrong to conclude that Al Qaeda's affiliate in Yemen has eclipsed the organization's core, the Post said.

Even under constant pressure from Predator attacks, Al Qaeda has proven remarkably resilient. Officials cited by the daily also stressed that it is surrounded by other militant groups in Pakistan that share its violent aims.

The Pakistani origin US citizen Faisal Shahzad, who planted a failed bomb at Times Square earlier this year, for example, said he had been trained by the Pakistani Taliban.