The three armored vehicles roll into the village of Niki Kaz on the outskirts of Kandahar. As the Canadian soldiers pass out candy and notepads to a crowd of gathering villagers, a village elder wearing a gray turban warns them about local militants.
Two weeks earlier, "there were Talibs coming through in a convoy with two land cruisers and four motorbikes.We are trying to prevent them placing bombs," says Pir Mohammed.
The patrol, part of the Canadian Provincial Reconstruction Team based in nearby Kandahar City, stays less than 20 minutes before moving on to the next village. That leaves locals under the protection of Afghan police, who Pir Mohammed says are too scared to leave their offices.
In the wake of Operation Medusa last summer, in which hundreds of insurgents were killed in fighting around Kandahar, military officials hoped that development workers would move into to fill the vacuum. That never happened. Almost a year later, most of Afghanistan's four southern provinces are out-of-bounds to aid workers who cannot engage with local communities while clad in body armor and traveling in Humvees.
"It is a strange time. There is Western interest in putting money in here, but little idea of how to move forward or who might do it," says Rangina Hamidi, a Kandahar-based aid worker with the Baltimore-based Afghans for Civil Society.
NATO commanders have acknowledged that there is no military solution to the conflict in southern Afghanistan and have said that improved governance and reconstruction are crucial.
The US and British governments have stepped up aid to the restive south, and the Afghan Ministry of Rural Reconstruction and Development (MRRD) has expanded its offices in Kandahar.
But finding Afghan aid agencies who are willing to work on projects in outlying southern districts has become a thorny problem – especially in areas where international troops visit districts to inspect aid work, such as the canal-clearing project in Niki Kaz.
"When they [NATO soldiers] monitor the projects themselves, they come with tanks, with weapons, and this affects our staff badly," says Abdul Salaam Siddiqi, the deputy director of the Voluntary Association for the Rehabilitation of Afghanistan (VARA).
Mr. Siddiqi says his agency has rolled back its activities steadily over the past two years and now operates only in provincial capitals in the south.
Delivering aid in outlying districts has become impossible, and eight staff members have been killed since 2002.
"We face many problems. The Taliban have arrested our engineers there and captured our vehicles," he explains.
When the Taliban ran the country, VARA operated all over Afghanistan.Now, with the lines about who is in control of villages becoming increasingly blurred, it has become more restricted.
"In some places, the Taliban will kill all government officials, and in others, the government has links with the Taliban so they cannot guarantee our safety," he adds.
The government's flagship National Solidarity Program, which allows communities to decide how to spend aid money, has taken only preliminary steps in Helmand and only operates on a very small scale in Uruzgan.
"Insecurity is obviously a threat, and in provinces such as Zabul and Uruzgan it is very difficult to find implementation partners," says Mohammad Tariq Ishmati of the MRRD's Kandahar office.
But problems with deteriorating security are not confined to Afghanistan's most violent areas. Across the country, aid agencies are finding themselves caught in factional conflicts or are the targets of criminal attacks.
A report last month by the Agency Coordinating Body for Afghan Relief (ACBAR) warned that donors' political objectives are distorting aid delivery.
The US Agency for International Development (USAID), by far the country's largest donor, allocates more than half of its aid to the four restive southern provinces, the report said. The report cited a disproportionate amount of aid that was being delivered to insecure or opium-producing areas.
This approach overlooks the massive development needs in comparatively stable areas and "creates perverse incentives – for provinces to create insecurity to attract resource," the report added.
The unbalanced distribution has had observable effects on the aid effort. Over the last year, the situation in the north and west – areas once branded peaceful by the international community – has deteriorated sharply.
There have been more attacks on aid agencies in the north and west than in the south during the first quarter of this year, the majority of them criminal, according to statistics from the Afghanistan NGO Security Organisation.
Only 12 percent of the attacks on aid agencies nationwide occurred in the south, where 40 percent of the incidents linked with the insurgency took place.
By contrast, 26 percent of incidents took place in the north and northeast – a region that saw only 5 percent of the actual armed military conflict.
The conflict has also spread closer to Afghanistan's capital, Kabul, where most international aid agencies are based. The past month has seen clashes between suspected Taliban and government forces in western Herat's Shindand districts and in Kapisa, just 75 kilometers north of the capital Kabul.
In this climate, entering new areas to deliver aid means first gaining the trust of local communities – a method that takes time and still more aid resources.
"Where trouble arises there is no quick fix," says Anja de Beer, the head of ACBAR.