(Repeats to additional subscribers)
By Steve Holland and Phil Stewart
WASHINGTON, Feb 25 (Reuters) - President Barack Obama has told the Pentagon to prepare for the possibility that no U.S. troops will be left in Afghanistan over President Hamad Karzai's refusal to sign a joint security agreement.
The United States has said that after its formal drawdown of troops from Afghanistan by year's end, it could leave a contingent of as many as 8,000 for counter-terrorism operations against al Qaeda targets and to train Afghan forces. But Karzai's refusal to sign a security deal has frustrated the White House, which has been forced to abandon an earlier demand that he sign the deal in weeks, not months.
"Specifically, President Obama has asked the Pentagon to ensure that it has adequate plans in place to accomplish an orderly withdrawal by the end of the year should the United States not keep any troops in Afghanistan after 2014," the White House said in a statement on Tuesday.
Obama told Karzai in a phone call on Tuesday that he had given the order to the Pentagon, the White House said. Obama's phone call to Karzai was the first substantive discussion between the two leaders since June.
Defense Secretary Chuck Hagel was carrying the modified U.S. position to Brussels for a meeting with NATO defense ministers that starts on Wednesday.
"Every time a day goes by our options narrow as to what options we have," Hagel told reporters shortly before flying to Brussels.
The United States currently has about 33,600 troops in Afghanistan and is withdrawing the force in line with Obama's vow to largely end a 12-year mission that begun after the Sept. 11, 2001 attacks.
Staking out a new position, the White House statement said "we will leave open the possibility of concluding a BSA (bilateral security agreement) later this year. However, the longer we go without a BSA, the more challenging it will be to plan and execute any U.S. mission."
And the longer both countries go without a security deal, "the more likely it will be that any post-2014 U.S. mission will be smaller in scale and ambition," the statement said.
Hagel said he would not be discussing firm deadlines while in Brussels. "I'm not going to NATO...to give timelines."
Hagel said planning for what is known as "the zero option" is a prudent step given that Karzai has made clear he is unlikely to sign the security deal. Karzai has suggested any security deal could wait until after Afghan elections in April.
"As the United States military continues to move people and equipment out of the Afghan theater, our force posture over the next several months will provide various options for political leaders in the United States and NATO," Hagel said in a statement.
A senior government official from neighboring Pakistan predicted dire consequences should the United States withdraw completely.
"In my opinion zero option should not be an option. In my opinion zero option means civil war in Afghanistan," the official told reporters in Washington.
A NATO official in Brussels said the alliance's headquarters was aware of Obama's statement. NATO officials and diplomats had been playing down the delay in Karzai signing the agreement in recent days.
"We will continue to develop our planning and assess the political and security conditions, so that we can take the appropriate decisions at the right time," the NATO official said. (Additional reporting by Jeff Mason and David Brunnstrom in Washington and Adrian Croft in Brussels; Editing by Susan Heavey and Grant McCool)
Our Standards: The Thomson Reuters Trust Principles.