Afghanistan and the United States have agreed on a draft of a long-awaited deal that will define the scope and nature of a US presence in the country for up to a decade after the pullout of most NATO combat troops in 2014.

Ryan Crocker, US ambassador to Kabul, and Afghan national security adviser, Rangin Spanta, initialed copies of the agreement on Sunday, paving the way for US President Barack Obama and his Afghan counterpart, Hamid Karzai, to review it.

"After much hard work together, we are pleased that we are close to completing negotiations on [the] Strategic Partnership," a US Embassy spokesman in Kabul told reporters.

"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. We believe this agreement supports that goal," he said.