There is one big problem: where do they go?

With the insurgents in control of vast swaths of the Afghan countryside, they are now focusing their offensives on a string of provincial capitals.

In Herat Friday, residents were streaming out of some neighbourhoods after being warned over loudhailers and radio to evacuate.

"We can hear the gunfire," said resident Ahmed Zia, adding the Taliban had entered the Karbas suburb where he lives a few days ago and were hiding out in houses and shops.

"We completely evacuated this area... we have nothing left and we do not know where to go."

Abdullah, who comes from the same neighbourhood, said the insurgents burst into his home and ordered him and his family to leave.

"There are eight or nine Taliban on the roof of our house," he said.

"If the security forces hit there, everything will be destroyed. Then where should we go?"

- Buses, cars, and even on foot -

On Friday, an AFP correspondent saw dozens of people leaving.

In buses, cars, and even on foot, they filed past a government mortar post as security forces casually lobbed bombs at an unseen enemy.

One man beat a cow with a stick to get it moving along the road; another coaxed two goats, bleating with indignity.

The exodus is being repeated across the country, with hundreds of thousands displaced by fighting that escalated in May when US-led foreign forces began the final stages of a withdrawal due to be completed by the end of the month.

Emboldened, the Taliban have now encircled a string of regional capitals -- although whether they have the numbers and firepower to take them remains to be seen.

One Taliban tactic appears to favour infiltrating the outskirts of cities, and then launch commando raids on strategic local government or police buildings.

Poorly trained auxiliary Afghan forces lack the morale or equipment to put up much resistance, but the Afghan military is sending elite troops to particularly vulnerable centres in the hope of turning the tide.

To do that, they have to flush out the insurgents with air strikes or artillery, and so are clearing the areas of civilians first.

That isn't easy, particularly in areas already bursting with people who recently arrived after fleeing fighting elsewhere.

In Kandahar, Afghanistan's second-biggest city, more than 150,000 people flooded in last month to escape fighting, only for the war to come to them.

"I was at home when the Taliban came and told me 'we are fighting whether you stay at home or not," said another man in Herat Friday.

"Our family all fled," he added, saying half of them sought shelter elsewhere in the city, and the rest in a nearby town.

"This is our situation and our misery is great," he said.