There was a reassuringly familiar feeling for Haji Sher Ahmed Ahmadi as he aimed the RPG launcher at the Taliban position behind a derelict building. He had fired an older version of the same weapon three decades ago, as a young man fighting the Russians.

He would much rather have been at his farm tending to the crops, which needed attention, he says, but felt he could not ignore the call of duty with the insurgents at the gates of Herat and threatening to storm the city.

Pointing out that he was an experienced mujahideen, Haji Sher Ahmed had requested to be on the front line and, according to his comrades, acquitted himself so well that Talib snipers started seeking him out. After a dozen attempts, they eventually managed to hit him in the head.

“It wasn’t a very serious injury, luckily; it was one of the Talibs the Pakistanis had not trained that well, not like when the Russians shot me all those years ago – they did a good job,” says the old warrior, his craggy face breaking into a grin.

“So I went back to the front line the next day. But Commander Khan told me to go and rest. I went back again the following day, but again he sent me back, saying I should rest and be fit for the next battle, as this thing is going to go on for a long while.”

The Commander Khan in charge of operations is Mohammed Ismail Khan, a redoubtable former mujahideen leader against the Russians and the Taliban, who has now organised the city’s defences, mobilised volunteer forces, and is leading the fight at the age of 70.

It is, says the man known as “The Lion of Herat”, one of the most important campaigns of his life.

The Taliban are also carrying out relentless attacks on Kandahar and Lashkar Gah. Those two cities, however, are in the Pashtun south, from where the Islamist group traditionally draw their support. Capturing Herat in the west, a traditional stronghold of adversaries, would be a huge boost to the Taliban’s claim to be establishing an emirate over the whole of the country.

With soldiers and weapons in short supply from the government in Kabul, which was apparently caught by surprise at the speed of the Taliban advance following the hasty withdrawal of US-led forces on the orders of President Biden, Haji Sher Ahmed and eight of his nine sons are among around 6,000 who volunteered and are now taking part in the fighting.

“Believe me, if this new Taliban take over they will be worse than the Russians. We need to stop them. I didn’t have to ask my sons to join, they just did. I have friends, neighbours who did the same,” he wants to stress. “This is our country, our Herat; we are not going to let these people come and take it over. Everyone wants to contribute: we have stopped them coming into Herat city, and now we are pushing them back.”

At the start of the week it was Herat that seemed likely to be the first of the three cities to fall, with the UN organising an airlift of its local staff and families, and reports of local government officials shredding documents in panic.

Fierce fighting is still going on in the suburbs, but the jihadist surge to the city centre has been pushed back. There are said to be a number of factors behind this: the insurgents being further away from their reinforcement lines in Pakistan; the resilience of the volunteer and government forces; and air strikes by Afghan and US warplanes, including the use of B52s from Diego Garcia, which have had a significant impact.

The Taliban still come into the city to carry out lethal attacks. On Wednesday evening a popular and effective police commander, Wahid Kohastani, was killed after being tracked down at his office in the latest in a series of assassinations of public officials and others who have spoken out against the Islamists.

What is happening in Herat is having repercussions elsewhere in the country.

Volunteer battalions are being formed in other cities and towns. President Ashraf Ghani has announced a national mobilisation plan. Even evening chants of “Allahu Akbar”, from people gathered in the streets and on the rooftops in defiance of the insurgents, are being emulated in other cities. The Taliban have complained about “infidels” using sacred slogans. They have also complained about the ferocity of the tactics used by Herati forces, and the western bombing.

The losses suffered by the Islamist group in Herat and elsewhere are said to be one of the reasons for a change in Taliban tactics, after they used a suicide bomber and gunmen in this week’s attack in Kabul, killing 13 people and injuring two dozen more.

While the Taliban complain about western air strikes, Ismail Khan – while stressing he had no fondness for either the Russian or the American military presence in his country – has no doubt about the real foreign enemy now.

“The war in Herat is being led by Pakistan. This is not the Taliban’s war, they are just being used as tools,” he declares. “This is a war between Pakistan and Afghanistan. We didn’t accept Russian occupation of our country, why should we accept Pakistani occupation? We have to fight for our country, just as we did against the Russians.

“The Taliban claim they have changed. But just look at what they are doing in the areas they have taken, the killings and the oppression. People don’t want that, and that is the reason they are volunteering to defend their homes and their country.”

Gul Mohammed Husseini wishes that people did not have to take up guns, but says what is happening leaves little choice. So the 58-year-old businessman took out his Kalashnikov AK-47, kept wrapped in oilcloth in a trunk, and volunteered to fight.

Like many of the others in the force, he was once part of the resistance against Soviet forces. “We are all getting on in years now, but some of the skills are still left I think,” says Mr Husseini. “There are also a lot of young people as well. I do not have any sons, but I have three daughters and they are one of the reasons why I am fighting. They won’t be able to stay in this country if the Taliban take over. If they cannot get away abroad, their lives would be unbearable. My wife supports me totally in what I am doing; everyone knows what is at stake.”

Haji Sher Ahmed also speaks of the importance of his wife’s support. “I have only had one wife: this may not seem strange to you, but I am from a generation and an area where this was not common,” he says. “Despite the problems we have, we are happy with all we have achieved – in our family, in our city, she knows what we have to do.”

Lifting his shirt to show scars left from when he was shot fighting the Russians – the bullet entering beside his heart and exiting through his back – he continues: “We have had tough experiences. I survived this, there are risks, but we cannot be afraid now when we face such a dangerous time for our country.”