The Taliban reportedly raised their flag above a key border post between Afghanistan and Pakistan, and claim it is now under their control.
Several videos have been shared on social media which showed the white Taliban flag fluttering above the Spin Boldak crossing near Kandahar.
Afghan officials have denied the post has fallen, although pictures on social media show the militants talking to Pakistani border guards.
In recent weeks, the militants have made speedy advances across the country, taking a series of border posts from Afghan forces, including crossings with Iran, Tajikistan and Turkmenistan.
It comes as the US withdraws its forces from Afghanistan ahead of an 11 September deadline set by President Joe Biden.
The Taliban – a fundamentalist Islamist militia who were pushed out of power by the US invasion nearly 20 years ago – have also taken control of a number of key roads as they seek to cut off supply routes to major cities.
The border post is the second busiest crossing between the countries. It links the city of Kandahar to Pakistan’s ports and seas, around 900 trucks pass through each day.
The crossing would be a major prize if the Taliban continue to hold it.
It would give the Taliban a significant customs revenue from the trade which flows back and forth and would provide direct access to areas in Pakistan, where Taliban leaders and fighters are known to have been based for many years.
