MOGADISHU (Reuters) - Somalia on Saturday called for the creation of a special humanitarian force to protect food aid convoys and camps in the famine-hit Horn of Africa country.

Islamist rebels mostly retreated from the capital Mogadishu last weekend but the threat of guerrilla-style attacks such as suicide bombings remains despite their battlefield defeat.

The government and a 9,000-strong African peacekeeping force admit they do not control all of the capital even after the rebel withdrawal, placing thousands of Somali refugees who are streaming into Mogadishu searching for food in danger.

The pullout by Al Qaeda-affiliated Al Shabaab insurgents has raised hopes that humanitarian groups will be able to step up aid deliveries after years of obstruction by the militant group.

Somali Prime Minister Abdiweli Mohamed Ali held a joint news conference with Valerie Amos, UN emergency relief coordinator, visiting the capital.

"We met today with Valerie Amos... we have discussed the current humanitarian situation in Somalia and the best way that we can assist with humanitarian aid to the people," said Ali.

"We have also raised the issue of creating a special humanitarian force, which has dual purposes. First to secure and protect the food aid convoy, and to protect the camps and stabilise the city and fight banditry and looting."

Ali did not say who would make up such a force.

Earlier this month, government troops fired shots and fought among themselves as some looted food meant for famine victims provided by the World Food Programme at the Badbaado camp near the city.

On Saturday, Somali police and the African Union troops said they had discovered 137 artillery shells in a disused house in the capital and destroyed them.

"The extremists were storing up large stocks of munitions in order to make improvised bombs to launch a campaign of terror in Mogadishu," said Lt. Col. Paddy Ankunda, spokesman for the AMISOM peacekeeping force that backs Somali's beleaguered government.

"Large areas of the city have to be cleared of these types of weapons stores and secured in the longer term so that the city can return to some semblance of normality and to do this we need more troops."

Amos shocked

Amos called for improved security for food convoys, and said she was shocked at the conditions after touring a hospital and meeting Somalis who had walked long distances to find food.

"The prime minister and I discussed the importance of security to ensure that humanitarian operations can continue... I am confident that with an improvement of security we will be able to do more to help those people who are desperately in need," she said.

"I was shocked to see some of the children at the hospital that I visited, and I can't imagine what it feels like to be a parent of these children suffering that level of malnutrition."

A cholera epidemic is spreading in the country, especially among people driven to the capital by a lack of food and water.

About 3.6 million people in Somalia are at risk of starvation. Some 12.4 million people in the Horn of Africa - including Somalia, Kenya, Ethiopia and Djibouti - are affected by the worst drought in decades, according to the United Nations. Tens of thousands of people have already died.

Amos was scheduled on Sunday to visit Dadaab, the world's largest refugee camp just over Somalia's border in neighbouring Kenya. Declared full in 2008, it has seen an influx of about 1,500 Somali refugees a day since late July.