U.S. President Barack Obama on Thursday said the United States is on track to achieve its goals in Afghanistan, but the achievements made there are "fragile and reversible."

In releasing the administration's review of his war strategy that saw the deployment of 30,000 additional troops, Obama said the war "continues to be a very difficult endeavor, but ... we are on track to achieve our goals."

Obama said because of the new strategy, senior al-Qaida leadership is now under more pressure than any other time, as more of its senior leaders have been killed, and it was harder for them to travel.

The Afghanistan and Pakistan Annual Review, which offers a national security staff-led assessment of U.S. strategy in Afghanistan and Pakistan, reaffirms the strategy's "core goal" to disrupt, dismantle, and eventually defeat al-Qaida in the Afghanistan-Pakistan region and prevent its return to either country.

The terror network led by Osama bin Laden is "hunkered down," Obama said, but at the same time warning "it will take time to ultimately defeat al-Qaida."

Though weakened, al-Qaida remains a threat to the United States and its interests, and Pakistan and Afghanistan continue to be the operational base for the group responsible for the 9/11 attacks, the review's authors wrote.

Obama said he was committed to the beginning of U.S. troops drawdown in July, 2011, but noted for the gains to be sustained over time, "there is an urgent need for political and economic progress in Afghanistan."

In addition to acknowledging the cooperation given by the Afghan and Pakistan governments, including Pakistan's offensives in its tribal regions against extremists, Obama claimed "progress has not come fast enough, so we will continue to insist to Pakistani leaders that terrorist safe havens within their borders must be dealt with."

Obama also confirmed he would visit Pakistan next year and pledged support to Islamabad.

"We'll speed up our investment in civilian institutions and projects that improve the lives of Pakistanis," said Obama.

Durable progress rests on denying al-Qaida safe haven in western Pakistan and restoring basic stability and security in Afghanistan, according to an unclassified summary of the review.

Speaking after Obama, Secretary of State Hillary Clinton and Pentagon chief Robert Gates both stressed the importance of cooperation from Pakistan.

Gates said Pakistan needs to do more to control the flow of extremists along its border with Afghanistan, while Clinton said the administration will work to "close the gap" between Kabul and Islamabad.

As for the troops withdrawal, Gates said he hopes as progress increases in Afghanistan, troops withdrawal can accelerate. He said he's confident Afghans can begin taking control of their own security starting in July. Obama also said the administration will begin transition to new phase in war with Afghan-led security starting in July.

Obama ordered the deployment of 30,000 additional troops to Afghanistan late last year, but the troops made few progress in changing the outlook of the war as casualties of the war mount. The review is the first comprehensive look at whether Obama's strategy is working before the scheduled beginning of withdrawal in July, 2011. NATO allies have agreed to a timeframe of beginning the security transition to Afghan national forces in 2011 through 2014.

Jessica Mathews, president of thinktank Carnegie Endowment for International Peace, questioned the strategy of increasing force in Afghanistan, saying the actual reality in Afghanistan is as the United States increases its troops presence there, "the Taliban has gotten stronger, and Karzai's state has gotten weaker."

She stressed that as long as the government of Afghanistan remains weak, the tactical gains by U.S. forces will not translate to winning a military victory.

The war strategy is also held in dim view by the intelligence community. The New York Times on Wednesday quoted two new classified National Intelligence Estimates as saying although gains have been made by U.S. and NATO forces in the war, the failure of Pakistan to shut down militant sanctuaries in its tribal region bordering Afghanistan gave insurgents free pass across the border, undermining the efforts on the Afghan side.