Earlier, Taliban militants raised their flag on the bridge across the border River Panj, which separates Tajikistan and Afghanistan.

A Taliban spokesman said that the terrorist group had captured Afghanistan's biggest trade crossing with Iran.

"The port of Islam Qala is now under our full control and we will try to put it back in operation today," Zabihullah Mujahid, a spokesman for the insurgents said, as quoted by the AFP.

The Taliban's claim could not be verified as there has been no confirmation of the border crossing's fall from the Afghanistan government.

Islam Qala is one of the country's main ports of entry; Kabul uses it to trade with Iran.

Earlier, US President Joe Biden said that a complete US withdrawal of US service members from Afghanistan will conclude on 31 August. Biden also said that the Taliban is unlikely to be able to seize control of the country after US servicemen depart.

Afghanistan is torn in a confrontation between government forces and the Taliban, who have seized significant territories in rural areas and launched an offensive against large cities. Tensions have flared up as the withdrawal of foreign troops from the country is nearing its end.

In recent days, thousands of Afghan government soldiers have fled to neighbouring Tajikistan, escaping from the Taliban, which took over 70% of the Afghan-Tajik border under its control. Uzbekistan, which shares a border with Afghanistan, has refused to accept Afghan soldiers trying to cross borders.

The departure of US and NATO forces from Afghanistan, scheduled to be completed by 11 September, has been met with a surge in violence, with dozens of districts in Afghanistan's rural north falling to the Taliban movement in the past weeks.