A push into the heart of darkness with Charlie Company

Julius Cavendish joins US troops running the gauntlet of Taliban ambushes in Zhari

West of Kandahar City, deep in southern Afghanistan, is an area foreign troops call the "heart of darkness".

US soldiers from Charlie Company, 1st Btn 12th Infantry Regiment, who patrol there are under Taliban surveillance almost at once. As soon as they head into the lush patchwork of irrigation ditches, grape fields and tightly packed mud compounds that are known officially as Zhari district, they almost invariably run into ambushes.

With a high-ranking Taliban commander codenamed "Cyclops" back in the area, and normally bustling villages suddenly deserted, a fight seemed inevitable when they pushed west through Zhari last week. And, sure enough, it soon came. After several hours of cat and mouse with invisible opponents, there came a high-pitched fizz followed by the loud burst nearby of a rocket-propelled grenade (RPG). Soldiers were ducking, scrambling and running for cover in a single jerky movement. Insurgents opened fire with small arms.

"Told you we'd be bored before something happened," Specialist Justin Jun said.

Within minutes Kiowa gunships were growling overhead, launching volleys of Hellfire missiles at the attackers. Under the din of return fire, two squads pushed forwards quickly. "Put the gun up there and start looking," Captain Duke Reim shouted at a startled private. "Either you die scared or you die fucking fighting."

Although the insurgents treat Zhari as a personal fiefdom, the coalition lacked the troops to challenge them until five months ago, when a US light infantry battalion deployed here.

"We're trying now to control these brand new areas and it takes time and it takes resources," Lieutenant Mark Morrison, a platoon leader, said. "I think the hardest thing to accept for both us and the people back home is that it takes casualties."

A single Canadian rifle company tried to cover the district before the Americans arrived, while a contingent of 2,500 troops was responsible for the 20,858 sq mile province of Kandahar and its million inhabitants.

Relative to their number, the Canadians took heavier casualties than any other major troop contributor. Yet despite the scant attention it receives, the area is of enormous symbolic importance. Seven kilometres west of Charlie Company's patrol route lay the village mosque where a one-eyed cleric called Mullah Mohammad Omar preached in the early 1990s: the "heart of darkness" is the birthplace of the Taliban.

It's an "If we can hold [the ground the Taliban began on] then where can't we hold type-of-thing," Lt Morrison said.

There are also pressing strategic reasons for Nato's invigorated presence here. In his assessment of the war last year, General Stanley McChrystal reported that the Quetta Shura Taliban – the most prominent of the insurgent groups operating in southern Afghanistan – was extending its influence over Kandahar City and its approaches.

To lose Kandahar City would be a huge blow for the Afghan government. It is the political and spiritual heart of southern Afghanistan, and of the Pashtun ethnic group from which the insurgents draw most of their support. Putting an infantry battalion in Zhari blocks a well-trodden infiltration route into the city.

The presence of the US infantry regiment has also slashed the number of IED strikes on Highway 1, the artery that connects the south to the rest of the country. Heading west along the two-lane stretch of asphalt are supply convoys vital to British, US and Danish forces as they prepare to storm Taliban strongholds in central Helmand.

"If the road doesn't stay open ... that will hinder our ability to supply the forward lines," the battalion commander, Lieutenant Colonel Reik Andersen, said. "When we first got here... there were just monuments to Taliban success and government failure along that highway – burned-out military vehicles, convoy trucks scattered all over."

The Taliban in Zhari have repelled coalition onslaughts before. In 2006, the Canadians lost four men here in fierce fighting when a last-minute change of plan saw them push into the district during Operation Medusa.

The Nato campaign coupled with the McChrystal strategy of protecting population centres are more considered. With time and reinforcements the American forces around Kandahar City will push out, wrapping outlying villages in a "security bubble".

But building trust with local communities is time-consuming. Many are terrified of the attack helicopters the Americans use. They also know that spies in their midst inform the Taliban of any co-operation with the foreign soldiers. The insurgents themselves blend in seamlessly.

The Americans' most fruitful argument is that the Taliban's use of homemade bombs is as much a threat to farmers as it is to the Afghan security forces and their foreign allies.

The initial RPG strike last week wounded a young man the Americans had been questioning. A medic pulled shrapnel from his face and staunched the bleeding but about an hour after the fight began he collapsed and began drifting in and out of consciousness. Under a barrage of covering fire a Black Hawk helicopter touched down to evacuate him.

But the militants had slipped away. "You almost never see them," Jun said. "You only hear their shots."