The US and Afghanistan have reached a deal on a long-delayed strategic partnership agreement that assures the Afghan people their key American ally will not abandon the country militarily or financially for years after 2014, the deadline for most foreign forces to withdraw.

The agreement is key to the US exit strategy in Afghanistan because it provides guidelines for any American forces who remain after the withdrawal deadline and for financial help to the impoverished country and its security forces. For the Afghan government, it is a way to show its citizens that its key allies are not just walking away.

"Our goal is an enduring partnership with Afghanistan that strengthens Afghan sovereignty, stability and prosperity and that contributes to our shared goal of defeating al-Qaeda and its extremist affiliates," US embassy spokesman Gavin Sundwall said on Sunday. "We believe this agreement supports that goal."

After 10 years of US-led war, Taliban and al-Qaeda-linked insurgents remain a threat and as recently as a week ago, they launched a large-scale attack on the capital, Kabul, and three other cities.

The draft agreement was worked out and initialled by Afghan national security adviser Rangin Dadfar Spanta and US ambassador Ryan Crocker and must still be reviewed in both countries and signed afterward by the Afghan and American presidents.