"After escaping across the border into Pakistan in 2001 and 2002, the Al Qaeda's leadership established a safe-haven there," Obama said in his Afghan-policy speech at the West Point Military Academy in New York.
Although a legitimate government was elected by the Afghan people, it has been hampered by corruption, the drug trade, an under-developed economy, and insufficient security forces, he said.
"Over the last several years, the Taliban [ Images ] has maintained common cause with the Al Qaeda, as they both seek an overthrow of the Afghan government. Gradually, the Taliban has begun to take control over swaths of Afghanistan, while engaging in increasingly brazen and devastating acts of terrorism against the Pakistani people," the US President said.
Shortly after taking office, Obama said he approved a long-standing request for more troops.
"After consultations with our allies, I then announced a strategy recognising the fundamental connection between our war effort in Afghanistan, and the extremist safe- havens in Pakistan.
"I set a goal that was narrowly defined as disrupting, dismantling, and defeating the Al Qaeda and its extremist allies, and pledged to better coordinate our military and civilian effort," Obama said, adding since then, the US has made progress on some important objectives.
"High-ranking Al Qaeda and Taliban leaders have been killed, and we have stepped up the pressure on the Al Qaeda worldwide," he said.
"In Pakistan, that nation's army has gone on its largest offensive in years. In Afghanistan, we and our allies prevented the Taliban from stopping a presidential election, and -- although it was marred by fraud -- that election produced a government that is consistent with Afghanistan's laws and Constitution," he said.
After 9/11, Obama said, within a matter of months, the Al Qaeda was scattered and many of its operatives were killed.
"The Taliban was driven from power and pushed back on its heels. A place that had known decades of fear now had reason to hope," he said.
Obama said that the cancer of violent extremism has taken roots in the border region of Pakistan and argued the need for the US and its allies to successfully treat it.
"We are in Afghanistan to prevent a cancer from once again spreading through that country. But this same cancer has also taken root in the border region of Pakistan. That is why we need a strategy that works on both sides of the border," he said.
"In the past, there have been those in Pakistan who have argued that the struggle against extremism is not their fight, and that Pakistan is better off doing little or seeking accommodation with those who use violence," he said.
But in recent years, as innocents have been killed from Karachi to Islamabad [ Images ], it has become clear that it is the Pakistani people who are the most endangered by extremism. "Public opinion has turned."
"The Pakistani Army has waged an offensive in Swat and South Waziristan. And there is no doubt that the United States and Pakistan share a common enemy," he argued.
Obama said the US was committed to a partnership with Pakistan that is built on a foundation of mutual interests, mutual respect, and mutual trust.
"We will strengthen Pakistan's capacity to target those groups that threaten our countries, and have made it clear that we cannot tolerate a safe-haven for terrorists whose location is known, and whose intentions are clear," Obama said.
"America is also providing substantial resources to support Pakistan's democracy and development. We are the largest international supporter for those Pakistanis displaced by the fighting.
"And going forward, the Pakistani people must know: America will remain a strong supporter of Pakistan's security and prosperity long after the guns have fallen silent, so that the great potential of its people can be unleashed," he said.
An effective partnership with Pakistan, Obama said is one of the three core strategies of his administration along with a military effort to create the conditions for a transition; a civilian surge that reinforces positive action.