Obama signs 10-year deal on surprise Afghan trip

President Barack Obama slipped into Afghanistan under the cover of darkness last night on the anniversary of the killing of Osama bin Laden to sign an agreement cementing US commitment to the nation after American combat troops leave.

Alongside the Afghan President Hamid Karzai, Mr Obama declared, "Together, we're now committed to replacing war with peace".

The partnership spells out the US relationship with Afghanistan beyond 2014, covering security, economics and governance. The deal gives both sides political cover: Afghanistan is guaranteed its sovereignty and promised it won't be abandoned, while the US gets to end its combat mission in the long and unpopular war but to keep a foothold in the country.

The deal does not commit the US to any specific troop presence or spending. But it does allow it to keep troops in Afghanistan after the war ends for training Afghan forces and targeted operations against al-Qa'ida.

At a signing ceremony in Kabul, Mr Obama said the agreement paves the way for "a future of peace" while allowing the United States to "wind down this war".

Mr Karzai said his countrymen "will never forget" the help of US forces over the past decade.

Mr Obama was greeted upon arrival at Bagram airfield by Ryan Crocker, the US ambassador to Afghanistan. Mr Obama then flew by helicopter to the presidential palace in Kabul.

The President was to be on the ground for about seven hours in Afghanistan, where the US has been engaged in war for more than a decade. Journalists travelling with Mr Obama on the flight had to agree to keep it secret until he had safely finished a helicopter flight to the nation's capital, Kabul, where Taliban insurgents still launch lethal attacks.

Large parts of Kabul surrounding Mr Karzai's palace were locked down for Mr Obama's arrival, with police sealing off streets around the city's walled Green Zone, home to most embassies and Nato's Afghanistan headquarters.