US President Barack Obama opened a NATO summit on Sunday saying the world backed his plan to end war in Afghanistan, as President Hamid Karzai pledged his bloodied state would no longer be a ‘burden’.

Leaders of more than 50 nations stood in solemn silence as a bugler's lament recalled the heavy cost of a conflict that has killed over 3,000 coalition soldiers, maimed thousands more and left tens of thousands of Afghans dead.

As war weary western publics pine for an exit, the summit was set to endorse a withdrawal strategy and seek firm commitments from alliance states to train and bankroll Afghan forces to ensure a decade of sacrifice is not wasted.

Obama, fresh from corralling European leaders to unite behind a plan to save the euro at the G8 summit, switched to commander-in-chief in talks with Karzai ahead of the summit, three weeks after his dramatic flight into Kabul.

"We're confident that we are on the right track, and what this NATO Summit reflects is that the world is behind the strategy that we've laid out," Obama told reporters.

"Now it's our task to implement it effectively," he said, adding that progress had been possible partly through the ‘tremendous resilience of the Afghan people and the sacrifices of coalition troops’.

Karzai said his country no longer wanted to be a ‘burden’, urging the international community to complete a security transition to his Afghan forces as it pulls combat troops, currently numbering 130,000, by the end of 2014.

"Afghanistan... is looking forward to an end to this war and a transformational decade in which Afghanistan will be working further for institution building and the development of sound governance in the country," he said.

Along with reaffirming the 2014 deadline, the summit is expected to back Obama's plan to cede the lead in combat missions to Afghan forces next year, while making a commitment to securing $4 billion in annual funds for Afghan forces.

A long-term commitment to Afghanistan, without a huge foreign troop footprint, is the cornerstone of a new Strategic Partnership Agreement between Washington and Kabul meant to signal Afghanistan will not be abandoned.

$1 billion for Afghan

A Western official said on Sunday that nations with troops in Afghanistan had pledged roughly $1 billion to bankroll Afghan security forces after 2014. The bulk of the funding is expected to come from the United States.

Obama's second hometown summit – he hosted the APEC forum in his native Honolulu, Hawaii in November – went ahead under a massive security operation as normally bustling Chicago streets were deserted and monitored by police.

Boats with machine guns patrolled a river near Obama's hotel and the police and Secret Service enforced a wide security perimeter around the conference center hosting the first summit of the 28-member North Atlantic Treaty Organization on US soil in more than a decade.

The meeting took place as the 63-year-old organization confronts shifting 21st-century realities and shrinking defense budgets.

"Though the times may have changed, the fundamental reason for our alliance has not," Obama said, adding that "in good times and in bad our alliance has endured, in fact it has thrived."

Despite carefully constructed images of unity, there were some signs that the strains of the decade-long Afghan war spawned disagreements.

‘No rush for exits’

France has shaken up the carefully crafted withdrawal plan with new President Francois Hollande saying that he plans to pullout French troops by late 2012, a year earlier than planned.

But NATO chief Anders Fogh Rasmussen vowed: "There will be no rush for the exits. We will stay committed to our operation in Afghanistan and see it through to a successful end."

"Germany supports NATO's idea: We went into Afghanistan together and we want to withdraw from Afghanistan together," agreed German Chancellor Angela Merkel.

Apart from Afghanistan, Obama and fellow leaders will take other key decisions, activating the first part of a missile shield for Europe, despite fierce Russian opposition and announcing a slew of military cooperation projects to cope with mounting austerity.

Washington is also hoping that Pakistani President Asif Ali Zardari will agree to reopen key NATO supply routes into Afghanistan closed in November after US air strikes killed 26 Pakistani troops.

But the US-Pakistani talks on reopening vital supply routes for NATO forces in Afghanistan have stumbled over Islamabad demand to charge steep fees for trucks crossing the border, a senior US official said.

The official confirmed that Pakistan has proposed an exponential increase in fees, from the current rate of about $250 per truck to ‘thousands of dollars’.

Governments are feeling the pinch as Europe's debt crisis forces budget cuts across the board, and to cope NATO will announce more than 20 joint projects to pool military hardware as part of a so-called ‘Smart Defense’ initiative.