President Barack Obama has ordered the Pentagon to plan for a full American withdrawal from Afghanistan by the end of this year should the Afghan government refuse to sign a security agreement with the U.S, the White House said Tuesday.

But in a call with Afghan President Hamid Karzai, Obama also said the U.S. could still keep a limited troop presence in Afghanistan after 2014 if the agreement is ultimately signed. He acknowledged that Karzai was unlikely to sign the bilateral security agreement himself, leaving the fate of the continued U.S. troop presence in Afghanistan to the winner of the country’s April elections.

“We will leave open the possibility of concluding a BSA with Afghanistan later this year,” the White House said in a summary of the call between the two leaders. However, the White House added that “the longer we go without a BSA, the more likely it will be that any post-2014 U.S. mission will be smaller in scale and ambition.”

Tuesday’s call was the first known contact between Obama and Karzai since June, underscoring the White House’s frustration with the Afghan leader’s stubborn refusal to sign the security agreement. The White House has repeatedly said it would not leave American troops in Afghanistan without the agreement.

Defense Secretary Chuck Hagel called Obama’s order to the Pentagon “a prudent step” given the likelihood that Karzai will not sign the agreement. However, he said the Pentagon would also continue to make plans for a possible U.S. mission in Afghanistan after this year, which would focus on counterterrorism and training Afghan security forces.

Hagel will discuss the future of the U.S.-led mission in Afghanistan with NATO leaders during a summit this week in Brussels.

(AP)