The Punjab Valley, a mountain to the north of Kabul, is an inaccessible area with a long history of resisting the last major holdout and rebel group against Taliban rule.
Fighting between the Taliban and the National Resistance Front (NRF) has been going on for two weeks. Taliban forces have been deployed in Panjshir province and surrounding areas in recent weeks and captured three districts in the valley on Monday, he said.
Overnight clashes between the Taliban and the National Resistance Front of Afghanistan (NRF) began late Thursday and were very intense, an NRF source said.
“They (Taliban) are using their last force, but the clashes are still going on,” the sources said.
On Thursday morning, NRF spokesman Fahim Dasti said in an audio message that the Taliban had lost 40 troops in an ongoing attempt to enter Panjshir.
Ali Nazari, another spokesman for the group, said on Thursday that several heavy equipment and weapons destroyed by the Taliban had also been lost.
CNN has not independently confirmed Taliban deaths.
Separately, the Taliban source provided videos of the fighting and its aftermath. CNN could not verify the location or when videos were filmed.
On Wednesday, Taliban leader Panjshiris called for an apology and a ceasefire but agreed that talks had not yielded any results so far. He said the situation should be “resolved peacefully”, but did not directly address the claims of renewed fighting and casualties.
The Panjshir Valley has been the center of Afghan guerrilla warfare and has long withstood foreign aggression from the British Empire army to Soviet forces and the Taliban.
The rugged, inaccessible landscape plays a role in its defensive success, giving the local forces an advantage over the invaders.
After the USSR, which controlled Kabul and large parts of the country in the 1980s, withdrew from Afghanistan in 1989, various factions of the Mujahideen – or Islamic holy warriors – split into groups and fought for control of the country.
Masood led the anti-Taliban offensive until he was assassinated by al Qaeda operatives two days before the September 11, 2001 attacks.
The coalition and the wider NRF, now led by Masood’s son, Ahmed Masood, vowed to continue the fight against the Taliban in the wake of his capture of Afghanistan.
Masood and the NRF are now gathering anti-Taliban forces in the Panjshir Valley, which includes local resistance forces as well as remnants of a former Afghan army.
“The Taliban have not changed, and they still dominate the country,” Masoud told CNN in an interview on Wednesday. “We oppose domination, intolerance, and oppression, bringing a political force on the majority population that does not support them.”
He and the NRF are still trying to negotiate with the Taliban – but so far that conversation has “not led to anything obvious.” Negotiations are underway in Charika, the capital of neighboring Parwan province.
“Negotiations have their limitations,” he said, quoting a prominent Prussian military general. “War is a continuation of politics, and if we face aggression, we will have to fight to defend our land, our people and our values, and we will have to start a resistance.”