BAGRAM AIR BASE: US President Barack Obama issued a new plea to Taliban insurgents to push forward with reconciliation talks as he made a surprise visit to US troops in Afghanistan.

In a presidential address on the first anniversary of the killing of Osama bin Laden, the US president said the "path of peace" lay before the Taliban who could be part of the future if "they break with Al-Qaeda."

"In coordination with the Afghan government my administration has been in direct discussions with the Taliban," Obama said in his address from the Bagram Air Base which has played a pivotal role in the US engagement in Afghanistan.

"We made it clear they can be a part of the future if they break with Al-Qaeda and abide by Afghan laws. Many members have indicated an interest in reconciliation.

"The path to peace is now set before them. Those who refuse to walk it will face strong Afghan security forces backed by the United States and our allies."

President said the goal of defeating the Al-Qaeda network was within reach, more than a decade after the September 11 attacks.

Obama said: "The goal that I set to defeat Al-Qaeda and deny it a chance to rebuild is now within our reach."

The US President said a "time of war" was ending in a moment of American renewal, on a secret trip to Afghanistan a year after ordering the death of Osama bin Laden.

In a highly political election-year address from outside Kabul, Obama showcased his record as a commander-in-chief who ended two long wars, and conjured up a new dawn for a nation exhausted by conflict and recession.

"This time of war began in Afghanistan, and this is where it will end," Obama said, recalling a "decade under the dark cloud of war," after US troops were drawn into the Afghan quagmire after the September 11 attacks in 2001.

"Yet here, in the pre-dawn darkness of Afghanistan, we can see the light of a new day on the horizon," said Obama, seeking to use political capital earned by bringing troops home to validate his request for a second White House term.

Obama earlier dropped from night skies into Kabul amid secrecy and tight security and signed a deal with President Hamid Karzai, cementing 10 years of US aid for Afghanistan after NATO combat troops leave in 2014.

"Neither Americans nor the Afghan people asked for this war, yet for a decade we've stood together," Obama said at the signing ceremony.

"We look forward to a future of peace. We're agreeing to be long-term partners," said Obama.

The pact, agreed last month, sees the possibility of American forces staying behind to train Afghan forces and pursue the remnants of Al-Qaeda for 10 years, but does not commit Washington to specific troop or funding levels for Afghanistan.

It is meant to send a signal to US foes that despite ending the longest war in US history, Washington intends to ensure Afghanistan does not revert to a haven for terror groups like Al-Qaeda.

But after a war that has cost the lives of nearly 3,000 US and allied troops, maimed tens of thousands more, saw thousands of Afghans killed and cost hundreds of billions of dollars, the future is deeply uncertain.

"The Iraq War is over. The number of our troops in harm's way has been cut in half, and more will be coming home soon. We have a clear path to fulfill our mission in Afghanistan, while delivering justice to Al-Qaeda," he said.

"As we emerge from a decade of conflict abroad and economic crisis at home, it is time to renew America," Obama said against a backdrop of military vehicles in their sandy desert liveries.

"A united America of grit and resilience, where sunlight glistens off soaring new towers in downtown Manhattan, and we build our future as one people, as one nation," Obama said.

Yet though he sought to put a capstone on the war, Obama's statement effectively meant that US troops could be fighting for two more years, and some could remain in danger for a decade more.

And Obama bluntly told American troops there was more suffering to come. (AFP)