The United States will remain in an armed conflict in Afghanistan — essentially at war — after the end of this year under rules for combat operations the Pentagon requested, and President Obama approved, early this month.

Senior administration officials said that Obama agreed that U.S. military leaders in Afghanistan are authorized to approve combat operations, using ground forces, manned aircraft and drones, under three sets of circumstances.

They include counterterrorism operations against al-Qaeda and other “transnational” terrorist groups, protection of U.S. forces engaged in training or other activities, and assistance to Afghan forces. Under those circumstances, U.S. forces probably will be engaged in direct combat with the Taliban and other groups that pose a threat to them or other members of the remaining international military coalition.

“Our expectation is that the Taliban and al-Qaeda will continue to directly threaten U.S. and other forces in Afghanistan,” said a senior administration official who spoke on the condition of anonymity.

The new authorizations appeared to be a shift away from Obama’s statement, made in May, that “America’s combat mission will be over by the end of this year. Starting next year, Afghans will be fully responsible for securing their country.”

In this image provided by NATO Training Mission - Afghanistan, a convoy of Afghan National Army HMMWVs line up in formation at the Kabul Military Training Center in Kabul in January 2011. (Ernesto Hernandez Fonte/AP)

Obama ordered a reduction in the number of U.S. troops to 9,800 by Jan. 1 and said their mission would be limited to training and advising Afghan forces and to counterterrorism against al-Qaeda. By the end of 2016, that number is to be reduced to about 1,000 U.S. military personnel attached to the U.S. Embassy in Kabul.

In explaining the newly approved rules, which have been sent to the Pentagon to be turned into formal orders, the senior official drew a distinction between America’s “combat mission” in Afghanistan, and necessary guidelines for “combat operations” that will continue in specific situations.

Several months of discussions about the authorities, which were first reported by the New York Times, culminated with a meeting in late October in which Obama and his senior national security team listened to and questioned Defense Secretary Chuck Hagel; Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff; and Gen. John F. Campbell, who commands U.S. and coalition forces in Afghanistan.

While some civilian officials objected to the scope of the Pentagon requests, Obama’s decision, made less than a week later, “essentially allows for an expanded set of counterterrorism authorities than what had previously envisioned — essentially giving the military status quo,” said another U.S. official.

A senior military official said the authorities were “not a license for offensive combat operations against the Taliban just because we still have U.S. capabilities in the country.” Officials said that a combat-capability was already built into planning for the 9,800 troops, and that the new authorities would not require additional resources.

International law uses the term “armed conflict” to refer to war. A determination that the war was over would require a different legal justification for combat operations than the one the administration has used since 2009 (as did its predecessor under former president George W. Bush).

With the new authorities, the senior administration official said, “as a matter of international law, we will remain in an armed conflict with al-Qaeda and the Taliban.” He said the same circumstances for authorizing combat — force protection, counterterrorism and assistance to Afghan forces — would also to apply to U.S. combat operations against Taliban subgroups, such as the Haqqani network, which are designated terrorists or pose a specific threat.

The official described debates within the administration as “a process in a legal way of defining the criteria and the thresholds for the use of those combat capabilities that would remain in theater, should they be needed. Going from combat to a non-combat mission doesn’t mean you go from full aperture to zero,” the official said.

“It was about a legal set of defining authorities, not about changing the mission, not about broadening the scope,” he said.

The official said the administration would also continue to use the Authorization for the Use of Military Force passed by Congress in 2001 to provide domestic legal justification for combat operations next year in Afghanistan. Obama said last year he wanted to “narrow” or repeal that authorization, since “the Afghan war is coming to an end.”

The definition of a threat justifying the use of U.S. combat forces is not spelled out in the new authorities, and is left largely to the discretion of commanders on the ground. “These authorities would reside at a fairly senior level of the military leadership,” the official said.

“I can’t give you an exact threshold” for use of the new rules, the official said. “That’s not how the authority is defined. It is limited; it’s not any circumstance.”

The official said that authorization for combat in counterterrorism operations against al-Qaeda remnants and associated groups that remain in Afghanistan was not news, and “has always been integrated into our plan.”

While Afghan forces hold primary responsibility for protecting themselves and coalition forces, a combat capability was deemed necessary to protect U.S. and coalition troops that came under attack or were threatened, again at the discretion of commanders. Military officials had asked to have those authorities specified to ensure that available resources were not withheld when needed.

“One of the things we’ve made clear in these authorities,” the senior administration official said, was that “we will do what we need to do using what we consider combat capabilities as a force protection matter as the need requires.”

The military also asked the president to determine “in cases where the Afghans were truly on their own and needed some assistance, what would be the authority to use our combat role to assist them?” the official said.

“It’s limited, there has to be a threshold. . . . It’s not a single checkpoint getting fired at,” and would depend on a commander’s determination of the availability of U.S. resources.

Ronald Neumann, a former U.S. ambassador to Afghanistan said that “it would have been intolerable for the American commander . . . to keep his aircraft on the ground while an Afghan unit was overrun because he was not authorized to use it.”

Karen DeYoung reported from Istanbul; Missy Ryan reported from Washington.