As U.S. President Barack Obama wrestles over options for Afghanistan, NATO's secretary general said Thursday the military alliance should begin handing more responsibilities over to Afghan forces.

Obama is considering whether to send tens of thousands more American troops to the war-torn country, as requested by his war commander Gen. Stanley McChrystal.

However on Wednesday, it was reported that Obama wouldn't accept any of the proposals before him without changes.

The news, proffered by a senior administration official under the cover of anonymity, came as U.S. ambassador to Afghanistan Karl Eikenberry was reported to have expressed strong dissent about a troop surge, and as the war loses popular support in most NATO countries involved in the fighting.

Meanwhile on Thursday, Anders Fogh Rasmussen issued a statement after meeting with British Prime Minister Gordon Brown in London. The release said the NATO head and Brown had agreed that the solution to the Afghanistan conundrum is to increase the transition to Afghan leadership.

"We can and should start next year to hand lead responsibility to Afghan forces in a co-ordinated way through NATO where conditions permit," Fogh Rasmussen said in the statement.

Brown also said this week that heavy-lifting responsibilities in the volatile southern Helmand province -- where the lion's share of Britain's troops are stationed -- could get underway as early as June.

German Chancellor Angela Merkel also maintains that a handover in the south should begin soon.

But confidence in Afghan leadership is at a low point, following a presidential election debacle rife with violence and widespread corruption and allegations of vote rigging.

Eikenberry, Obama's ambassador to the country, warned recently that a troop surge should not be considered unless there are improvements in the government's performance.

U.S. Secretary of State Hillary Clinton also worries about corruption and a "lack of transparency" in Afghanistan, she said Wednesday in Manila.

"We're looking to President Karzai as he forms a new government to take action that will demonstrate -- not just to the international community but first and foremost to his own people -- that his second term will respond the needs that are so manifest," Clinton said during a news conference.

Obama is still expected to send more troops to Afghanistan, but the 40,000 he was earlier expected to send is now in doubt.

During meetings Wednesday he called for revisions to draft strategies to ensure there is clarity around how and when responsibilities would be handed over to the Afghan government.

Canada's military commitment to Afghanistan is scheduled to end in 2011. It's not clear whether troops will remain in the country to focus on non-combat roles.

With files from The Associated Press