As US and other NATO troops begin to withdraw from the country by 2014, Washington is in talks with Karzai’s government to allow the US Military to retain a residual presence. The size of the force has not yet been determined, but could number between 2,500 and 12,000, according to US officials.

The stated aim of the plan is that soldiers would continue to train the Afghan army and police, and carry out attacks on Al-Qaeda militants.

“Our conditions are that the US intensify its efforts in the peace process, strengthen Afghanistan’s security forces, provide concrete support for the economy – power, roads, dams – and provide assistance in governance,” Karzai said at a ceremony at Kabul University. "When they do this, we are ready to sign [a partnership agreement].”

Previously, the US said that if 6,000 troops were kept behind in Afghanistan only the bases in Kabul and Bagram airfield would be maintained.

As the US-led International Security Assistance Force (ISAF) draws down troop deployments in Afghanistan, security in the country is still in a perilous state, with the Taliban able to operate largely with impunity.