The militant group has already claimed that it now controls about 100 of nearly 400 districts, triggering fears that the country may be inching back towards a civil war.
The US and other Nato members have agreed to pull out foreign troops following a commitment that the Taliban will not allow any terrorist group including Al-Qaeda to operate in the areas it controls.
As a result, US president Joe Biden set 11 September as the deadline for the withdrawal, a date that marks the 20-year anniversary of the 9/11 terror attack on America.
But a Taliban spokesman warned that if any foreign troop is left behind, including military contractors, how the group’s members proceed will be the decision of its leadership.
“We would react and the final decision is with our leadership,” Suhail Shaheen told the BBC, speaking from the Taliban’s Qatar office. He added that diplomats, non-governmental organisations (NGOs) and other foreign civilians would not be targeted.
“We are against the foreign military forces, not diplomats, NGOs and workers, and NGOs functioning and embassies functioning – that is something our people need. We will not pose any threat to them,” the Taliban spokesperson clarified.
He also described the withdrawal of the US forces from Bagram Airfield in Afghanistan last week as a “historic moment”.
Mr Shaheen also said many districts were now under their control after mediation as Afghan soldiers refused to fight.
Afghanistan’s government, meanwhile, says it ready for talks but the onus is on the Taliban to show its commitment to peace.
It was in October 2001, following the attack by al-Qaeda that the US-led forces ousted the Taliban from power in Afghanistan as the militant group was accused of harbouring al-Qaeda’s chief, Osama bin Laden.
Though the Taliban has committed to not harbour extremist groups such as al-Qaeda, the experts fear that may not remain the case.
For instance, former director of Afghanistan’s National Directorate of Security (NDS), Rahmatullah Nabil, tweeted: “Taliban have taken territories in Northern #AFG specifically Badakhshan with the help of Alqaeda (Al-Qaeda) & ETIM fighters.”
He said the Jaish ul-Nasr brigade of al-Qaeda and others were fully active.
On Sunday, more than 1,000 Afghan troops were said to have fled across the border into Tajikistan after Taliban advances in northern Afghanistan, according to the Tajik border guard service, while dozens of others were captured by insurgents.
Afghan president Ashraf Ghani spoke to his Tajik counterpart, President Emomali Rakhmon, to discuss the developments. Afterwards, the Tajik president’s office said that “special attention was paid to the escalation of the situation in Afghanistan’s northern areas adjacent to Tajikistan”.
It added that Mr Rakhmon expressed concern about “forced crossings” by Afghan security forces. Reuters news agency reported that Tajikistan is looking into setting up camps for potential refugees from Afghanistan.
Afghanistan’s national security adviser Hamdullah Mohib, who was in Moscow on Monday for security talks, said that government forces had not anticipated the Taliban offensive but would counter-attack.
Russia, which operates a military base in Tajikistan, said the Russian consulate in the northern Afghan city of Mazar-i-Sharif was suspending operations over security concerns, the Tass news agency reported.
Additional reporting by agencies