KABUL, Oct 4— The United States and Afghanistan have reached an impasse in their talks over the role that American forces will play here beyond next year, officials from both countries say, raising the distinct possibility of a total withdrawal — an outcome that the Pentagon’s top military commanders dismissed just months ago.
American officials say they are preparing to suspend negotiations absent a breakthrough in the coming weeks, and a senior administration official said talk of resuming them with President Hamid Karzai’s successor, who will be chosen in elections set for next April, is, “frankly, not very likely.”
“The time to conclude for us is now,” the administration official said on Friday. In the absence of a deal, “this fall, we are going to have to make plans for the future accordingly.”
The impasse, after a year of talks, has increased the prospect of what the Americans call the zero option — complete withdrawal — when the NATO combat mission concludes at the end of 2014. That is precisely the outcome they hoped to avoid in Afghanistan, after having engaged in a similarly problematic withdrawal from Iraq two years ago.
Moreover, a complete withdrawal from Afghanistan could be far costlier than it was in Iraq. It would force European powers to pull their forces as well, risking a dangerous collapse in confidence among Afghans and giving a boost to the Taliban, which remain a potent threat.
It could also jeopardize vital aid commitments. Afghanistan is decades away from self-sufficiency — it currently covers only about 20 percent of its own bills, with the rest paid by the United States and its allies.
“It is a practical truth,” the administration official said, that without a deal, “our Congress would not likely follow through on the assistance promises we’ve made, nor would other partners.”
Many contentious matters in the talks have already been settled, like legal immunity for American troops, which is what scuttled the Iraq deal, Afghan and American officials said. Yet officials on both sides say two seemingly intractable issues remain.
The first is Afghanistan’s insistence that the United States guarantee its security, much like any NATO ally, and the second is Mr. Karzai’s refusal to allow American forces to keep searching in Afghanistan for operatives of Al Qaeda. Instead, he has proposed that the United States give its intelligence information to Afghan forces and let them do the searching, said Aimal Faizi, a spokesman for the president.
American officials have rejected both Afghan proposals. The security pact is especially problematic, they say, because it could legally compel American forces to cross the border into Pakistan, resulting in an armed confrontation with an ally — and a nuclear-armed power.
“The deal is like 95 percent done,” said another American official in Washington, “and both sides are holding out.”
President Obama, in an interview with The Associated Press published Saturday, made what appeared to be a reference to the impasse in the talks, saying that he would consider keeping troops in Afghanistan “if in fact we can get an agreement that makes sure that U.S. troops are protected, makes sure that we can operate in a way that is good for our national security.”
“If we can’t, we will continue to make sure that all the gains we’ve made in going after Al Qaeda we accomplish, even if we don’t have any U.S. military on Afghan soil,” Mr. Obama said in the interview, which was conducted Friday.
Mr. Faizi said Mr. Karzai was now taking a lead role in the talks. But, he cautioned, the Afghan leader could not agree to a deal that allowed American forces to raid Afghan villages and not at the same time go after militant havens in Pakistan.
“Killing people in homes and killing people in villages is bringing the war on terror to Afghans,” Mr. Faizi said in an interview. “This is not focusing on the root and support systems behind the terror.”
Only months ago, top American generals, including Gen. Martin E. Dempsey, the chairman of the Joint Chiefs of Staff, dismissed the possibility that negotiations could falter. The Obama administration has been far more ambiguous. Over the summer White House officials began to seriously weigh the zero option.
The officials say they, too, would prefer that American troops stay in Afghanistan. But “at the right price,” said a senior European diplomat familiar with the American position. “The price that Mr. Karzai is asking is too high for Obama.”
The administration has instructed the lead American negotiator, Ambassador James B. Cunningham, to make one more push this month to bring Mr. Karzai around, officials said. It may consider letting the talks go into November, if necessary. But officials are loath to see the talks become an issue in the Afghan presidential campaign.
This week, the administration also considered sending Secretary of State John Kerry, who has a good relationship with Mr. Karzai, to personally intervene in the talks, American and Afghan officials said. But in a reflection of the administration’s deepening pessimism — and its preoccupation with other priorities — officials decided Mr. Kerry’s time was better spent on an Asian trip that Mr. Obama canceled because of the government shutdown, according to another American official, although that could change if there was movement in the talks in Kabul.
So for now, it is up to Mr. Cunningham, who has told his Afghan counterparts that talks would be suspended until after Afghanistan’s presidential election if no progress was made soon, according to Mr. Faizi and other Afghan and American officials.
Assuming the election takes place on time, it would still push talks to the middle of next year, and many Western officials in Kabul say the election could be delayed until the summer. In the estimation of many Western officials in Kabul and Washington, that is perilously close to the drop-dead date of Dec. 31, 2014. Mr. Karzai, who has served two terms, cannot run for a third.
Adm. James G. Stavridis, who retired in May as NATO’s military commander, said the logistics of organizing a post-2014 force could prove daunting if a deal was not struck soon. Each of the allies has separate logistics, training, supply and transportation requirements, and “we are getting close to the red line for people to be able to put those forces together,” Admiral Stavridis said Friday at a forum in Washington sponsored by the Fletcher School of Law and Diplomacy, where he is now dean.
The impasse in the talks has been apparent to negotiators since late summer, according to Afghan and Western officials. But both sides had kept the divisions quiet until this week, when the presidential palace issued a statement saying Mr. Karzai had told a gathering of tribal elders that he would not allow American military raids to continue after next year.
American officials have not issued any formal response to the palace’s statement. Officials said they did not want Afghans to see the deadline as a ploy. They discussed the talks only under the condition of anonymity.
Afghan officials, however, said they believed the deadline and the leaks were solely about pressuring them into signing a deal.
Mr. Faizi said the Afghan government had no deadline, and Mr. Karzai would rather wait to get “the right deal.”
The differences between the two sides are as much about perspectives as they are about the legalities of raids and bases and security arrangements. Afghanistan believes the threat posed by the Taliban is largely driven from Pakistan. In the American view, the Pakistani havens are but one facet of a conflict that is mainly internal.
It is a subtle difference, but one that informs diverging approaches to combating the Afghan insurgency, which remains a threat despite the American-led efforts to quash it that began with the invasion after the Sept. 11, 2001, attacks.
American officials have said they have no intention of fighting the Taliban after 2014. The bulk of the forces left in Afghanistan — administration officials have said they would total 9,000 or less — would train Afghan forces, which are already doing most of the fighting here.
But the United States wants to keep using Special Operations forces to target the roughly 75 operatives that American commanders estimate remain in Afghanistan.
“President Karzai says that has been happening for 12 years, and how come we cannot find them?” Mr. Faizi said. “How much longer will it continue? One year? Five years? Ten years?”
Ultimately, though, the issue is one of sovereignty, Mr. Faizi said. American-led forces have killed civilians in dozens of attacks, he said, and Afghanistan has concluded that foreigners cannot be trusted with the lives of innocent Afghans.
“After 2014, will any foreign military be free to go where it pleases and operate the way it pleases in Afghanistan?” Mr. Faizi said. “The answer is no.”
Eric Schmitt, Thom Shanker and Michael R. Gordon contributed reporting from Washington.