The Taliban said on Monday they had captured the last pocket of resistance in Afghanistan, the Panjshir Valley, as the top US diplomat flies to Qatar to try and handle the aftermath of the chaotic American withdrawal, ndtv.com reported quoting news agency AFP.

Soon after, the National Resistance Front (NRF) -- made up of anti-Taliban militia and former Afghan security forces -- said the fight against Taliban in Panjshir Valley "will continue".

Following their lightning-fast rout of Afghanistan's army last month -- and celebrations when the last US troops flew out after 20 years of war -- the Taliban turned to crush the forces defending the mountainous Panjshir Valley.

"With this victory, our country is completely taken out of the quagmire of war," chief spokesman Zabihullah Mujahid said.

However, the NRF said it was present in "strategic positions" across the Panjshir valley, adding "the struggle against the Taliban and their partners will continue".

Late Sunday, the so-called NRF acknowledged suffering major battlefield losses in Panjshir and called for a ceasefire.

The NRF includes local fighters loyal to Ahmad Massoud -- the son of the famous anti-Soviet and anti-Taliban commander Ahmad Shah Massoud -- as well as remnants of the Afghan military that retreated to the Panjshir Valley.

The group said in a tweet Sunday that spokesman Fahim Dashty -- a well-known Afghan journalist -- and General Abdul Wudod Zara had been killed in the latest fighting.

The Panjshir Valley is famed for being the site of resistance to Soviet forces in the 1980s and the Taliban in the late 1990s.

The NRF had vowed to fight the Taliban but also said it was willing to negotiate with the Islamists. But initial contact did not lead to a breakthrough.

The Islamist Taliban took control of the rest of Afghanistan three weeks ago, taking power in Kabul on Aug. 15 after the Western-backed government collapsed and President Ashraf Ghani fled the country.

"The NRF in principle agree to solve the current problems and put an immediate end to the fighting and continue negotiations," Massoud said in the Facebook post.

"To reach a lasting peace, the NRF is ready to stop fighting on condition that Taliban also stop their attacks and military movements on Panjshir and Andarab," he said, referring to a district in the neighbouring province of Baghlan.

A large gathering of all sides with the Ulema council of religious scholars could then be held, he said.

Earlier, Afghan media outlets reported that religious scholars had called on the Taliban to accept a negotiated settlement to end the fighting in Panjshir.

There was no immediate response from the Taliban.

On Sunday, the NRFA also confirmed that its main spokesman, Fahim Dashti, had been killed during the day. Dashti had survived the suicide attack that killed Massoud's father, Ahmad Shah Massoud, on Sept. 9, 2001, just days before the Sept. 11 attacks on the United States.

He had been one of the main sources of updates from the area as the Taliban pressed in on opposition forces, issuing a defiant series of statements on Twitter, vowing that resistance would continue.

Massoud, who leads a force made up of remnants of regular Afghan army and special forces units as well as local militia fighters, called for a negotiated settlement with the Taliban before the fighting broke out around a week ago.