The CIA is urging the White House to approve a significant expansion of the agency’s fleet of armed drones, a move that would extend the spy service’s decade-long transformation into a paramilitary force, U.S. officials said.

The proposal by CIA Director David H. Petraeus would bolster the agency’s ability to sustain its campaigns of lethal strikes in Pakistan and Yemen and enable it, if directed, to shift aircraft to emerging al-Qaeda threats in North Africa or other trouble spots, officials said.