The great challenge for Afghanistan's security forces is to prevent insurgents from influencing young men like Wazirwal.

Anti-militant operation The checkpoint at the centre of this latest incident was set up to prevent insurgents crossing over the border into Afghanistan, our correspondent says.

To prevent insurgents from discovering their identities, many lie to everyone, wives and family included, about their real jobs.

Without sufficient Iraqi forces, however, this process has been hampered and it has been more difficult to prevent militias and insurgents from sneaking back into cleared areas.

American soldiers cleared out trees and walls along the sides to prevent insurgents from hiding.

The United States hopes the conference will press both to do more to prevent insurgents from flowing over their borders.

The outpost was evacuated two days later, and bombed on October 6 by a B-1 bomber to prevent insurgents from looting the munitions abandoned in the hasty withdrawal.

One design constraint was that the patrol bases had to be able to see straight along the route to prevent insurgents gaining unmonitored access to the road.

A sweep through Dahana-i Gori immediately afterwards was supposed to prevent remaining insurgents from hiding in neighbouring provinces.

But while the Turks were still strong enough to crush an open insurgency, they could not prevent new insurgents and propagandists from filtering into the area.