The decision to consider ramping up the US presence in the war-torn country follows President Donald Trump's move to give Defense Secretary Jim Mattis the authority to set troop levels.
The Pentagon is preparing to send as many as 4,000 additional American forces to Afghanistan, a Trump administration official said on Thursday, hoping to break a stalemate in a war that has now passed to a third US commander-in-chief.
At that level, the deployment would be the largest of American manpower under Donald Trump's presidency.
The decision by Defense Secretary Jim Mattis could be announced as early as next week, the official said. It follows Trump's move to give Mattis the authority to set troop levels and seeks to address assertions by the top US commander in Afghanistan that he does not have enough forces to help Afghanistan's army against a resurgent Taliban insurgency.
However, the Pentagon cautioned that no final decision had been made.
"No decisions have been made," said Defense Department spokesman Jeff Davis, when asked about the reported troop increase.
The bulk of the additional troops will train and advise Afghan forces, according to the administration official, who was not authorised to discuss details of the decision publicly and spoke on condition of anonymity.
A smaller number would be assigned to counter terror operations against the Taliban and Daesh, the official said.
America's longest running conflict
The rising threat posed by Daesh, evidenced in a rash of deadly attacks in the capital city of Kabul, has only fuelled calls for a stronger US presence, as have several recent American combat deaths.
Although Trump has delegated authority for US troop numbers in Afghanistan, the responsibility for America's wars and the men and women who fight in them rests on his shoulders.
Trump has inherited America's longest conflict with no clear endpoint or a defined strategy for American success, though US troop levels are far lower than they were under former presidents Barack Obama and George W Bush.
In 2009, Obama authorised a surge of 30,000 troops into Afghanistan, bringing the total there to more than 100,000, before drawing down over the rest of his presidency.
Trump has barely spoken about Afghanistan as a candidate or president, concentrating instead on crushing Daesh in Syria and Iraq.
His predecessors both had hoped to win the war. Bush scored a quick success, helping allied militant groups oust the Taliban shortly after the September 11, 2001, attacks, before seeing the gains slip away as American focus shifted to the Iraq war.
In refocusing attention on Afghanistan, Obama eliminated much of the country's Al Qaeda network and authorised the mission that killed Osama bin Laden, but failed to snuff out the Taliban's rebellion.
There have been almost 2,400 US military deaths in Afghanistan since 2001. Three US soldiers were killed and another was wounded in eastern Afghanistan this weekend in an attack claimed by the Taliban.