The Taliban have captured a major border crossing between Afghanistan and Iran, according to Afghan officials.
Video footage appeared to show Taliban forces taking down the Afghan flag from the roof of the border customs office.
The Islam Qala crossing is one of the biggest trade gateways into Iran, generating an estimated $20m monthly revenue for the government.
The Taliban are rapidly retaking land across Afghanistan as the US-led mission removes the last of its troops.
The Americans earlier this week quietly abandoned Bagram airfield, a sprawling base that was the centre of US operations in Afghanistan and once held tens of thousands of troops.
The Taliban are thought to now control more than a third of the country's 400 districts, including an arc of territory from the Iranian border in the west to the frontier with China on the other side of the country.