The proposed deal between the US and Afghanistan over the presence of American troops post-2014 has hit a roadblock as both sides expressed differences over the timetable for signing the agreement.
While Washington prefers to seal the deal as quickly as the end of 2013, Afghan President Hamid Karzai has made it clear that Kabul intends to sign the pact only after the country's presidential election next year.
US State Department spokesperson Jen Psaki said: "We believe that signing sooner rather than later is essential to give Afghans certainty about their future before the upcoming elections, and enable the United States and other partners to plan for US presence after 2014.
"It is neither practical nor possible for us to further delay because of the uncertainty it would create."
White House spokesperson Josh Earnest echoed a similar view, but added: "We have not yet determined whether a troop presence will continue in Afghanistan."
If the agreement between the two countries gets the green light, it will allow the presence of about 15,000 foreign troops, more than half of them American, in the strife-torn country up to 2024.
The draft has resolved two thorny issues concerning authority over trying US soldiers and American troops raiding Afghan homes.
While the US has conceded its troops will not raid Afghan homes except in "extraordinary circumstances", Kabul has authorised the US to hold trials in cases involving disciplinary action against US troops.
The latest US remarks follow Karzai's address to a grand council of nearly 2,500 tribal leaders and local political figures.
In his remarks to the gathering, known as "Loya Jirga", Karzai said: "They will stay here for 10 more years to assist and train Afghan security forces and leave Afghanistan in 2024. This pact should be signed when the election has already taken place, properly and with dignity."
Karzai, who has already been president for two terms, cannot run for the next presidential election in Afghanistan under the country's constitution.
He said the deal would be helpful in bringing much-needed stability to Afghanistan in the next decade and added that leaders from scores of countries including Russia, India, and China are supporting the deal.
At the same time he made it clear that he no longer trusts the Obama administration and wants his successor to take the burden of signing such an agreement with the US.
The Afghan leader said: "My trust with America is not good. I don't trust them and they don't trust me. During the past 10 years I have fought with them and they have made propaganda against me."