Another significant threat to the homeland, Brennan said, was al Qaeda-inspired lone wolf attackers.
"This is the first counter-terrorism strategy that focuses on the ability of al Qaeda and its network to inspire people in the United States to attack us from within," Brennan said.
Discussing the rise of bin Laden's deputy, Ayman al-Zawahiri, to the leadership role of the terror network Brennan warned he "may very well attempt to demonstrate his leadership and al Qaida may try to show its relevance through new attacks."
Brennan said that al Qaeda affiliates, such as al-Shabaab in Somalia and al Qaeda in the Arabian Peninsula (AQAP) in Yemen, still pose a "serious direct threat" to the U.S.
As the U.S. begins the drawdown of troops from Iraq and Afghanistan Brennan said that working with foreign security forces, more targeted operations with special forces and drone strikes will be employed. "Going forward, we will be mindful that if our nation is threatened, our best offense won't always be deploying large armies abroad, but rather delivering targeted, surgical pressure to the groups that threaten us," he said.
Beyond al Qaeda, Brennan said the White House's counter-terror strategy will not necessarily target other groups designated as terror organizations but could put pressure on nations accused of supporting such groups.
"Our strategy is not designed to combat directly every single terrorist organization in every corner of the world, many of which have neither the intent nor the capability to ever attack the United States or our citizens," he said. "Our strategy recognizes that there are numerous nations and groups that support terrorism in order to oppose U.S. interests. Iran and Syria remain leading state sponsors of terrorism... So we will therefore continue to use the full range of our foreign-policy tools to prevent these regimes and terrorist organizations from endangering our national security."
In the meantime, Brennan said al Qaeda, the terror organization that has been a main focus of U.S. counter-terror efforts for nearly a decade, appears to be weakened and on its way out, similar to the way he described bin Laden shortly before his death.
"And we are left with that final image seen around the world -- an old terrorist, alone, hunched over in a blanket, flipping through old videos of a man and a movement that history is fast leaving behind," he said.