The measure would reduce the number of troops from 8,600 to 4,500 and would be the lowest number since the first days of the war in Afghanistan, which began in 2001.
It would pave the way for an exit from the United States that President Donald Trump remains determined to achieve.
While the decision is not final, Defense Secretary Mark Esper discussed the plan with NATO allies last week and the issue was reviewed at his meetings with NATO officials in Brussels on Friday.
"We will also follow up on our discussion on Afghanistan. NATO will continue to adjust our presence in support of the peace process," NATO Secretary General Jens Stoltenberg said with Esper on Friday before their meeting. "This will be done in close coordination with allies and partners."
Under the agreement signed with the Taliban in February, the United States pledged to withdraw all of its troops from Afghanistan next April, within 14 months of its signing, if the Taliban confirmed certain commitments in the agreement. The Taliban pledged to prevent terrorist groups from using Afghan territory to threaten the US and its allies, severing ties with groups that threaten the US and seeking intra-Afghan negotiations.
As part of that agreement, the United States also agreed to reduce the number of troops from approximately 13,000 to 8,600 in early July. The United States has already reached that figure of 8,600, ahead of schedule, two US officials told CNN.
It is unclear when the withdrawal of the additional 4,000 US troops will begin, a political decision in its final stages. US officials at the State Department and the Pentagon have reiterated that any reduction below the 8,600 mark would be "based on conditions."
"The levels of United States force in Afghanistan remain at the mid-8,000s. Further reductions beyond this number are based on conditions in accordance with the United States government's assessment of the overall security environment and Taliban compliance with the agreement between the United States and the Taliban, "said Pentagon spokesman Maj. Rob Lodewick. , he told CNN.
The State Department and the National Security Council did not respond to requests for comment.
Reduced levels will mean the United States will have difficulty carrying out missions
Under the plan to cut troop levels to 4,500 by the fall, the US military will likely have difficulty carrying out the missions it currently has in the country.
The training and advice of local Afghan forces will likely have to be reduced considerably in the event of such a drastic reduction, leaving Afghans vulnerable as the Taliban continue to attack the military and police.
The remaining US troops are likely to focus on counter-terrorism operations targeting ISIS's local affiliate, ISIS-K, which maintains a presence in the east of the country, as well as the remains of al-Qaeda. A recent UN report found that the Taliban have maintained ties to Al Qaeda despite the agreement between the United States and the Taliban.
But many will worry that the United States will withdraw too quickly.
Last month, the top US commander who oversees military operations across the Middle East said the conditions that would allow a full withdrawal of US forces from Afghanistan "have not been fully met," despite the agreement. with the Taliban.
"If conditions allow, we are prepared to go to zero, however the important phrase is if conditions allow. Those conditions would be, you know? Can we be sure that there will be no attack on us? I think those Conditions, frankly, if asked my opinion, those conditions have not been fully met, "said Gen. Kenneth McKenzie, commander of the United States Central Command.
Trump administration officials also acknowledge that the commander-in-chief is ultimately responsible for decision-making when it comes to troop levels.
"It is the prerogative of the president if he believes the conditions have been met and we could do it faster," Zalmay Khalilzad, the United States Special Representative for Afghanistan Reconciliation, told reporters earlier this month when Trump could withdraw before the elections. . "But the key is to know if the conditions have been met, and I think that is the most important issue, and we are monitoring it very closely."
Some U.S. officials are concerned that Trump may decide to withdraw all U.S. troops from Afghanistan ahead of the November election to fulfill a promise he made in the 2016 campaign, two U.S. officials told CNN.
But a US official familiar with the discussions said he believes the president would agree to the 4,500 figure because it would mean that there would be fewer troops than when President Barack Obama left office, allowing Trump to declare a campaign victory. electoral.
Trump's ambition to reduce troops in Afghanistan throughout his presidency was highlighted with new details by his former national security adviser John Bolton in his book, "The Room Where It Happened: A White Hose Memory," published this week. .
"I gave you what you asked for. Unlimited authority, no restrictions. You are losing. They are kicking your butt. You failed," Trump told then-Defense Secretary Jim Mattis in 2018, according to Bolton's book.
Bolton said this week that the straw in his White House departure was Trump's plan to invite the Taliban to Camp David. After Bolton left, the meeting did not happen, but the discussions continued culminating in the February signing.
Despite the agreement, the Taliban have continued to carry out deadly attacks against the Afghan government and civilians, but have not attacked US troops.
These attacks have devastated the Afghan government and created tension with the United States.
The US Army has carried out some defensive air strikes in defense of Afghan troops that have been attacked by the Taliban but, under the agreement, it cannot take any offensive action against the Taliban.
Last month, the Afghan government blamed the Taliban for a terrorist attack on a maternity ward at a hospital in Kabul last month, which killed more than a dozen people, including babies. It also prompted Afghan President Ashraf Ghani to announce that his country would resume offensive operations against the insurgent group after a series of deadly terror attacks.
Khalilzad tweeted that the United States government "evaluated" that ISIS-K carried out the horrible attack. However, other US officials were less confident that the Taliban were not involved or informed, citing the sophistication of the network involved in the attack, a US defense official and a source familiar with intelligence told CNN.
A small hope arose when the ceasefire between the warring parties was upheld during the three-day Eid al-Fitr Muslim holiday last month.
Secretary of State Mike Pompeo praised the ceasefire, saying he hopes Afghan and Taliban leaders "will not escalate the violence after Eid."
"This violence is counterproductive, deepens the complaints and prolongs the suffering of the Afghan people," said Pompeo.
But since Eid, Taliban attacks have continued.
On Monday, Afghan national security spokesman Javid Faisal tweeted that "last week was the deadliest in the past 19 years. The Taliban carried out 422 attacks in 32 provinces, killed 291 ANDSF members and wounded 550 more. " He also called the Taliban's violence "inconsistent with his rhetoric about peace."
Privately, US officials say it is untrue that last week was the deadliest, noting that the Taliban adhere to the deal by not attacking US forces.
Some US officials also expect Taliban violence to subside once intra-Afghan negotiations between the US and the Taliban begin and a political solution is in sight. However, those conversations that were supposed to start in the spring have not yet started.