WASHINGTON — The United States vowed Wednesday to pursue the "utter destruction" of Al-Qaeda, while refocusing its counter-terrorism strategy to combat the threat of home-grown terror.

The new strategy comes on the 10th year of the US-led "war on terror," launched by former president George W. Bush after the deadly September 11 attacks on the United States.

It is a "pragmatic, not ideological" approach to counterterrorism that "formalizes" the administration's approach since January 2009, said John Brennan, President Barack Obama's top counterterrorism advisor.

The new strategy, developed after US commandos killed Osama bin Laden on May 2 in Pakistan, also reflects "the extraordinary political changes" sweeping the Middle East and North Africa, Brennan said.

"This is the first counterterrorism strategy that designates the homeland as a primary area of emphasis in our counterterrorism efforts," said Brennan, who is also deputy national security adviser for homeland security.

Al-Qaeda still in the US crosshairs

The principal focus is "Al-Qaeda, its affiliates and its adherents," said Brennan, speaking at the Johns Hopkins School of Advanced International Studies in Washington.

"We aim to render the heart of Al-Qaeda incapable of launching attacks against our homeland, our citizens, or our allies, as well as preventing the group from inspiring its affiliates and adherents to do so," he said.

"This is a war -- a broad, sustained, integrated and relentless campaign that harnesses every element of American power," he said.

"And we seek nothing less than the utter destruction of this evil that calls itself Al-Qaeda."

With US forces pulling out of Iraq and preparing for a draw-down in Afghanistan, Brennan all but ruled out foreign adventures.

"If our nation is threatened, our best offense won't always be deploying large armies abroad but delivering targeted, surgical pressure to the groups that threaten us," he said.

President Obama, speaking at a press conference Wednesday, said that US military operations in Afghanistan and Pakistan have served to "severely cripple Al-Qaeda's capacities" and have "decimated some of the upper ranks of Al-Qaeda."

The terror network is "having a great deal of difficulty operating and financing themselves. We'll keep the pressure on," Obama said.

Brennan dismissed the new Al-Qaeda leader, Egyptian-born Ayman al-Zawahiri, as "an aging doctor who lacks bin Laden's charisma and perhaps the loyalty and respect of many in Al-Qaeda."

The "lone wolf" threat

The US strategy also takes into account the growing threat of domestic "lone wolf" attackers radicalized by online preachers.

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 stressed.

The best known of these attackers is Major Nidal Hasan, the US Army psychiatrist charged with killing 13 people and wounding 32 more in a November 5, 2009 shooting rampage at the Fort Hood army base.

On Wednesday, three men arrested in a sting operation for planning to attack two New York synagogues and to shoot down US military planes were each sentenced to 25 years in prison.

On June 23, two US men were charged with plotting to attack a military center in the northwestern US city of Seattle with machine guns and grenades, allegedly hoping to kill more people than Hasan did at Fort Hood.

The new counter-terrorist strategy also focuses on threat from Al-Qaeda affiliates in places like Yemen, Somalia, Iraq, and north Africa.

"As the Al-Qaeda core has weakened under our unyielding pressure," said Brennan, "it has looked increasingly to these other groups and individuals to take up its cause, including its goal of striking the United States."

Separately, Brennan said that Iran and Syria "remain leading state sponsors of terrorism."

"Hezbollah and Hamas are terrorist organizations that threaten Israel and our interests in the Middle East. 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," he said.

Regarding Pakistan, Brennan acknowledged that the relationship "is not without tension or frustration," but said that both sides were working to overcome differences.

"I am confident that Pakistan will remain one of our most important counterterrorism partners," he said.