Al-Qaeda weakened, under enormous strain: Obama

US President Barack Obama has said the information seized during the raid that killed Osama bin Laden showed the al-Qaeda terror network had "weakened" and was under "enormous strain."

"The information that we recovered from bin Laden's compound shows al-Qaeda under enormous strain," Obama said in a televised speech on troop withdrawal plans from Afghanistan.

A "weakened" al-Qaeda's information is confirmed from the huge catche of material recovered from the Abbottabad-safe house of bin Laden, he said.

"Laden expressed concern that al-Qaeda has been unable to effectively replace senior terrorists that have been killed, and that al-Qaeda has failed in its effort to portray America as a nation at war with Islam, thereby draining more widespread support," he said.

Al-Qaeda remains dangerous, Obama said, and US must be vigilant against attacks.

"But we have put al-Qaeda on a path to defeat, and US will not relent until the job is done. In Afghanistan, we've inflicted serious losses on the Taliban and taken a number of its strongholds. Along with our surge, our allies also increased their commitments, which helped stabilise more of the country," he said.

The US president said Afghan Security Forces had grown by over 100,000 troops, and in some province and municipalities, America has already begun to transition responsibility for security to the Afghan people.

"We will have to do the hard work of keeping the gains that we have made, while we drawdown our forces and transition responsibility for security to the Afghan government.

"And next May, in Chicago, we will host a summit with our NATO allies and partners to shape the next phase of this transition," Obama said.