International troops plan to stay in Afghanistan beyond the May deadline sparking concerns tensions in the country could escalate.
The administration of then-President Donald Trump signed an agreement with the Taliban early last year calling for the withdrawal of all foreign troops by May in return for the insurgents fulfilling certain security guarantees.
Trump hailed the accord - which did not include the Afghan government - as the end of two decades of war.
He reduced U.S. troops to 2,500 by this month, the fewest since 2001.
Now four senior NATO officials have said not all the troops would be taken out of the country by the end of April.
"There will be no full withdrawal by allies by April-end," one of the officials told Reuters.
"Conditions have not been met," he said on condition of anonymity because of the sensitivity of the matter.
"And with the new U.S. administration, there will be tweaks in the policy, the sense of hasty withdrawal which was prevalent will be addressed and we could see a much more calculated exit strategy."
As of October there were around 12,000 personnel from 38 NATO member states and partner countries deployed in support of the Resolute Support Mission in Afghanistan.
That number has since dipped to 10,000, according to NATO spokeswoman Oana Lungescu.
On October 7, 2021 it will be 20 years since the US entered Afghanistan.
Plans on what will happen after April are now being considered and likely to be a top issue at a key NATO meeting in February, the NATO sources said.
Peace talks between the Afghan government and the Taliban began in September in Doha, but violence has remained high.
"No NATO ally wants to stay in Afghanistan longer than necessary, but we have been clear that our presence remains conditions-based," Lungescu said.
"Allies continue to assess the overall situation and to consult on the way forward."
Kabul and some foreign governments and agencies say the
Taliban has failed to meet conditions due to escalated violence and a failure to cut ties with militant groups such as Al Qaeda, which the Taliban denies.
The administration of Joe Biden, who replaced Trump on January 20, has launched a review of his predecessor's peace agreement.
A Pentagon spokesman said the Taliban have not met their commitments but Washington remained committed to the process and had not decided on future troop levels.
The Taliban have become increasingly concerned in recent weeks about the possibility that Washington might change aspects of the agreement and keep troops in the country beyond May, two Taliban sources told Reuters.
"We conveyed our apprehensions, but they assured us of honouring and acting on the Doha accord," said a Taliban leader in Doha.
"What's going on, on the ground in Afghanistan, is showing something else.
"And that's why we decided to send our delegations to take our allies into confidence."
