Washington, May 18 - Leaders of the NATO nations, Afghanistan and Pakistan meet in Chicago on Sunday to set in motion the massive transition to end the costly war in Afghanistan and the post-2014 scenario in the country.

"The goal is to have an Afghanistan again that has a degree of stability such that forces like al-Qaeda and associated groups cannot have safe haven unimpeded, which could threaten the region and threaten US and other interests in the world," US National Security Advisor Tom Donilon said, outlining the issues that would figure at the key summit.

The summit to be attended by President Barack Obama as well as new President of France Francois Hollande, German Chancellor Angela Merkel and others would expect to hear that the US and NATO are not abandoning Afghanistan.

Pakistan President Asif Ali Zardari will also attend the summit.

The conference would outline key steps on timeframe of handing over security duties to the newly-raised Afghan Army as well as approve longterm bankrolling of these forces.

With Afghan forces assuming the lead role in 2013 for protecting the country and its government, Donilon said the NATO allies hoped to leave behind "a set of security assets that allow it to provide for that modicum of stability".

He said steps would be chalked out that will allow Afghanistan to protect itself against Al Qaeda and ensure that the United States' core goal -- making sure that Al Qaeda cannot again use Afghanistan as a base from which to target the West -- is met.

"So Chicago is a critical milestone in the next step towards a responsible ending of this war, towards our achieving, very importantly, our goals in this effort in Afghanistan," Donilon said in his briefing on the NATO Summit.

"That is that the mission will shift from the ISAF forces, the United States forces, as part of ISAF, being in the combat lead to stepping back and getting into principally a train-and-advise mode, with the Afghans going into the combat lead all over the country," he said.

According to US media, spending on the war in Afghanistan has skyrocketed since Obama took office to USD 118.6 billion in 2011. It was USD 14.7 billion in 2003, when his predecessor George W Bush turned his attention and American resources to the war in Iraq.

The summit comes as US lawmakers are expressing concern that inspite of a surge in US forces in Afghanistan, Taliban were getting stronger and gaining ground.

The lawmakers have also posed questions whether the draw down would mean the return of Pakistani and Iranian influence in the key parts of the country, in the south and the northwest.

Media reports have also said that the Obama Administration has lowered the bar significantly in Afghanistan after 11 years of combat.

But side-stepping such issues, Obama top aide said the summit would discuss and frame an agreement on the structure and sustainability of the Afghan national forces past 2014.

"That is, what should their size be, what should the mission be, and how will it be paid for -- Sustainment, of course, is a euphemism for how will it be paid for going after 2014. And we've made very good progress on this," Donilon said. PTI