The Taliban's claim to hold 90 per cent of Afghanistan's borders is an “absolute lie”, the defence ministry said on Friday, insisting that government forces were in control of the country's frontiers.

“It is baseless propaganda,” deputy spokesperson of the Ministry of Defence Fawad Aman told AFP, a day after the insurgents made the claim, which was not possible to independently verify.

The Taliban's claim on Thursday came after the group captured key border crossings with Iran, Tajikistan, Turkmenistan and Pakistan in recent weeks in a staggering offensive launched as US-led foreign forces began their final troop withdrawal from Afghanistan.

On Friday, Aman insisted government forces were in control of the country's borders and all “main cities and highways”.

And even as large-scale fighting decreased during this week's Eidul Azha holiday, the interior ministry accused the Taliban of killing about 100 civilians in the town of Spin Boldak along the border with Pakistan since seizing the crossing last week.

“Afghan security forces will soon take revenge on these wild terrorists,” interior ministry spokesman Mirwais Stanekzai said on Twitter.

“The Taliban whenever they get control [of territory], the first thing they do is destroy public facilities or public infrastructure, harass people and forcefully displace families,” Aman told AFP. “It happened in Spin Boldak too.”

With the withdrawal of American-led foreign forces all but complete, the resurgent Taliban now controls about half of Afghanistan's roughly 400 districts.

Earlier this week, Chairperson of the US Joint Chiefs of Staff General Mark Milley said the Taliban appear to have “strategic momentum” on the battlefield.

With the militants putting pressure on around half of the country's provincial capitals, Afghan troops are in the process of “consolidating their forces” to protect those major urban centres, Milley added.