"The ultimate decision was a more aggressive formulation, if you will, in terms of the timeline than what we had recommended," Petraeus said of U.S. President Barack Obama's announcement Wednesday that he will withdraw 10,000 troops Afghanistan this year and another 23,000 next year.
"The fact is that there's never been a military commander in history who has had all the forces that he would like to have with all the time, with all the money, with all the authority and nowadays with all the bandwidth as well," Petraeus told the U.S. Senate Select Committee on Intelligence.
There has "been important progress against al-Qaida in recent months, in particular," he said. "I will ensure that we maintain the relentless pressure that has enabled such progress."
Later, Petraeus noted that despite the killing of Osama bin Laden, al-Qaida continues to be a threat and one that he would monitor aggressively as head of the CIA.
If confirmed by the Senate, Petraeus wouldn't make a complete transition to the CIA until power is fully transferred to U.S. Air Force Gen. John R. Allen, who will take over operations in Afghanistan.
Running the CIA would put Petraeus in a position to "grade [his] own work," analyzing intelligence efforts in Afghanistan and Iraq. Petraeus has overseen those efforts as commander of the International Security Assistance Force and U.S. forces in Afghanistan since last July.
"I have views on the efforts in which I have been engaged; I have shared them in the past with the agency's analysts and I will do so in the future," Petraeus told the committee. "However, if confirmed, when I am in the Situation Room with the president, I will strive to represent the agency position."
Petraeus said that his transition from commander to the head of the CIA wouldn't involve "militarization" of the intelligence agency.
"If confirmed, I will, in short, get out of my vehicle alone on the day that I report to Langley," he said.
"I wanted this job. This is something that was not a month or two or three in making," Petraeus said. "I'm taking off the uniform that I've worn proudly for 37 years to do this job I think in the right way."