At least 17 people have reportedly been killed and more than 40 wounded in celebratory gunfire in Kabul, according to Reuters.
The celebratory gunfire came as the Taliban claimed to have taken Panjshir Valley, north of Kabul - the last province not seized by the extremist group.
One Taliban leader said, per Reuters: "By the grace of Allah Almighty, we are in control of the entire Afghanistan. The troublemakers have been defeated and Panjshir is now under our command."
Opposition leaders denied the territorial gain, however.
While sources have not ascertained whether the Taliban had indeed emerged victorious in the province, if it is true, it would mean that the group now controls all parts of Afghanistan - something they failed to achieve during their previous regime between 1996 and 2001, Independent reports.
Former Vice President Amrullah Saleh, one of the leaders of the opposition forces, said, per Reuters, that his side will be persistent in their defense against the Taliban.
"There is no doubt we are in a difficult situation. We are under invasion by the Taliban," he was reported as saying. "We have held the ground, we have resisted."
Ahmad Massoud, another commander leading resistance forces against the Taliban, also dismissed the claim that the Taliban seized Panjshir.
He said: "News of Panjshir conquests is circulating on Pakistani media. This is a lie."
Claims that Panjshir has fallen to the Taliban comes after reports of intense fighting and casualties in the valley, which is walled off by mountains with the exception of a narrow entrance.
It has resisted Soviet occupation in addition to the previous Taliban regime that came to an end in 2011 after US military intervention.
Independent also reports that Kabul airport has now reopened for aid deliveries and will soon begin service of civilian flights after recent disruptions to the running of the airport, the Qatari ambassador to Afghanistan reportedly confirmed.
The airport had closed during recent evacuations of US citizens and Afghan refugees. Furthermore, the runway is undergoing work before it can return to its usual service.
The Qatari ambassador reportedly said that a few domestic flights have already taken off from the airport.