Mr Saleh has called on fellow Afghans who oppose the Taliban takeover to join other fighters in Panjshir – where he has proclaimed himself as the country’s rightful ruler. He tweeted: “Join the resistance. I will never, ever and under no circumstances bow to Taliban terrorists.”
Mr Saleh stayed in Afghanistan after president Ashraf Ghani fled as chaos ensued in Kabul, the country’s capital.
Those set to counter the Taliban include Afghan special forces and commandos.
They received training from American and British forces, purportedly including the Special Air Service (SAS).
A source told Sun Online: “We are thousands and many more are coming. We have local people as well.
“It is not ordinary resistance. It is the resistance of thousands of trained forces who are familiar with every inch of the soil and who has excellent experience in fighting the terrorists for the past 20 years.
“I am not going to die before destroying the Taliban. We will fight till the last bullet.”
Panjshir’s mountainous landscape is currently controlled by checkpoints and guards.
It is reported soldiers from the Afghan army have also been heading to Panjshir to join the resistance with their weapons.