"Al-Qaida and its allies -- the terrorists who planned and supported the 9/11 attacks -- are in Pakistan and Afghanistan," the president said. "Multiple intelligence estimates have warned that al Qaeda is actively planning attacks on the U.S. homeland from its safe-haven in Pakistan. And if the Afghan government falls to the Taliban -- or allows al-Qaida to go unchallenged -- that country will again be a base for terrorists who want to kill as many of our people as they possibly can."
Listen to President Obama's remarks on Afghanistan: In addition to directing more troops and resources to Afghanistan, Mr. Obama called for increasing aid to neighboring Pakistan as it confronts mounting attacks by militants.
Just hours before Mr. Obama's speech, a suicide bomber attacks a crowded mosque in the Khyber tribal area of northwestern Pakistan, killing at least 50 people and leaving more bodies buried in the rubble of the building, according to Pakistani officials, reported the Washington Post.
The United States also will launch an intensive diplomatic effort to gain international support for its Afghan-Pakistan plan from Russia, China, India, Saudi Arabia and even Iran, according to the Associated Press.
Obama's special envoy to the region, Richard Holbrooke, will hold bilateral meetings with Afghanistan and Pakistan every six to eight weeks, Reuters reported.
Pakistan embraced the concept of a regional approach and the plan as a whole. "We are in favour of this policy," Prime Minister Yousaf Raza Gilani told reporters, quoted Reuters. "They have accepted our position (that) army action alone is not a solution for all these problems."
President Obama said the overall goal is to "disrupt, dismantle and defeat" the terrorist havens in Pakistan while trying to bolster Afghanistan's military and society. He called the situation in Afghanistan "increasingly perilous."
"For the Afghan people, a return to Taliban rule would condemn their country to brutal governance, international isolation, a paralyzed economy, and the denial of basic human rights to the Afghan people -- especially women and girls," he said.
But the president also said the United States is not in Afghanistan to "control that country or to dictate its future. We are in Afghanistan to confront a common enemy that threatens the United States, our friends and allies, and the people of Afghanistan and Pakistan who have suffered the most at the hands of violent extremists."
Mr. Obama plans to send 4,000 more troops, who will come from the 82nd Airborne Division at Fort Bragg in North Carolina, whose mission will be to train and expand the Afghan army to lead counterinsurgency efforts.
The president also plans to send hundreds more U.S. civilians to help Afghanistan rebuild its infrastructure and revenue-generating programs. The president also pledged to seek an increase in civilian assistance from other countries and groups like the United Nations and international aid groups.
The strategy will cost billions of dollars, though Obama aides would not give specifics before the speech, reported the AP.
President Obama ordered a review of U.S. policy in Afghanistan and Pakistan as one of his first official acts after taking office on Jan. 20.
In Afghanistan Plan, Exit Strategy Remains a Sticking Point