The immunity deal would be part of a larger bilateral security agreement being negotiated between Washington and Kabul for post-2014, Afghan President Hamid Karzai said in a joint press conference with President Obama at the White House.
In exchange for an immunity deal, the White House agreed to hand over complete control of U.S.-run detention facilities in the country, as well as pull out American military units stationed inside Afghan villages.
"With those issues resolved, as we did today ... I can go to the Afghan people and argue for immunity for U.S. troops in Afghanistan in a way that Afghan sovereignty would not be compromised," Karzai said on Friday.
Lack of an immunity deal for U.S. troops was a key factor in the failed attempt to set up a postwar security deal in Iraq and set the stage for the recent wave of sectarian violence against Iraqi forces and civilians in the country.
The immunity deal would reverse a Pentagon decision to retain custody of hundreds of suspected Taliban fighters captured by American and NATO forces in Afghanistan.
U.S. forces officially transitioned control of all American detention facilities to Kabul last year, but retained control over those high-value detainees.
The drawdown of U.S. forces inside Afghan villages is part of Obama's decision to accelerate the handover of security operations to Afghan forces, announced during Friday's press conference.
As part of that deal, Afghan National Security Forces will take the lead in all security missions in Afghanistan with U.S. support by this spring, Obama said during the press conference.
That transition was scheduled to take place sometime in early 2014, ahead of the American withdrawal from the country. American troops will remain in country after the handover this spring, but will take a backseat to Afghan commanders.
That said, "by the end of next year — 2014 — the transition will be complete [and] this war will come to a responsible end," Obama said.
While the terms of an immunity deal for a postwar U.S. presence may be complete, both leaders declined to go into details regarding the number of American troops that will be left behind after 2014.
"I'm still getting recommendations from the Pentagon, and our commanders on the ground in terms of what that would look like," Obama said. "When we have more information about that, I will be describing that to the American people."
A final decision on the American postwar presence in Afghanistan is expected no later than November, Deputy National Security Adviser for Strategic Communications Ben Rhodes told reporters Tuesday.
Administration officials would have a "better idea" on when that decision would come down as negotiations with Kabul and the Pentagon continue, Rhodes said at the time.
Gen. John Allen, the top U.S. commander in Afghanistan, sent his postwar recommendations to Defense Secretary Leon Panetta late last year. That plan includes scenarios requiring between 6,000 and possibly as many as 20,000 troops in country after the administration's deadline.
The proposal with the smallest number of American soldiers suggested by Allen would be tasked strictly with counterterrorism operations inside Afghanistan.
The 10,000-man option will allow U.S. forces to continue training Afghan forces while continuing the counterterrorism mission. The largest troop scenario includes upwards of 20,000 American boots on the ground in Afghanistan, carrying out counterterrorism, training and some conventional combat missions in the country after 2014.
Administration officials are also keeping the so-called "zero option" on the table, which would abandon any plans to leave a residual U.S. troop presence in the country once American commanders end all combat operations next year.
For his part, Karzai said the size of whatever residual U.S. troop presence is left in Afghanistan is irrelevant, noting that both countries are focused on ensuring that eventual force will be able to support Afghan troops after the American drawdown.
"Numbers are not going to make a difference to the situation in Afghanistan," Karzai said. "It's the broader relationship that will make a difference to Afghanistan and beyond in the region."