Several officials said yesterday the decision was made in recent days to expand the authority of US commanders to strike the Taliban and better support and assist the Afghan forces when needed in critical operations, using the US troops already in the country.
There is a broad desire across the Obama administration to give the military greater ability to help the Afghans fight and win the war.
The officials were not authorised to talk publicly about the discussions so spoke on condition of anonymity.
The decision comes as the Afghans struggle with a resurgent Taliban, particularly in the south.
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But it is fraught with political sensitivities because President Barack Obama had made clear his commitment to get US forces out of Afghanistan. That effort, however, has been stalled by the slow pace of the development of the Afghan military and the resilience of the Taliban.
The decision will give US forces greater flexibility in how they partner with Afghan forces, but the new authorities must be used in selective operations that are deemed to have a strategic and important effect on the fight.
The results have been daunting: The UN says 3,545 Afghan civilians were killed and 7,457 wounded in 2015, most of them by the Taliban.
The US has continued to conduct counterterrorism strikes against al-Qaida and Islamic State militants in Afghanistan. But strikes against the Taliban were largely halted at the end of 2014, when the US-led coalition's combat role ended.
General John Nicholson, the top US commander in Afghanistan, has discussed with Defence Secretary Ash Carter his recommendations for moves the US can make to further assist the Afghans. And there have been repeated conversations with the White House in recent weeks.