The United States wants the Afghanistan government to sign a bilateral security agreement in matter of weeks if a contingent of U.S. troops is to remain there after 2014, the White House said on Monday.
The Afghan government had ignored U.S. demands for it to sign a framework security agreement by the end of 2013, after protracted negotiations that have strained relations between the two countries.
U.S. officials say unless a deal is reached to keep upwards of 8,000 U.S. troops inside the country after 2014, the United States might instead completely withdraw from the country.
Afghanistan President Hamid Karzai has expressed skepticism at the U.S. threat for a complete withdrawal.
"Our position continues to be that if we cannot conclude a bilateral security agreement promptly, then we will be forced to initiate planning for a post-2014 future in which there would be no U.S. or NATO troop presence in Afghanistan," White House spokesman Jay Carney told reporters.
Without a deal, the United States could pull out all troops, the so-called "zero option," leaving Afghan forces to battle the Taliban on their own.
Carney said the longer the issue drags into 2014, "the more likely that outcome will come to pass" in which the United States would leave no troops behind for the training of Afghan forces or counter-terrorism purposes.
"Look, I don't have specific deadlines or other policy decisions to announce today. But I can tell you that we are talking about weeks, and not months. And, you know, the clock is ticking," Carney said.