Somalia is suffering its worst famine in 60 years, and more than 29,000 children under the age of five have died in the last 90 days in the country's south alone, according to US estimates. Fighters allied with an Al-Qaeda-linked militant group, Al-Shabab, have blocked many aid organisations from the south and have complicated efforts to help those in Mogadishu.

"The information we are receiving is that there is a retreat from the city. This is a golden victory for the Somali people and we are committed to ensure that peace and order is restored to those areas," said government spokesman Abdirahman Omar Osman. However, Al-Shabab spokesman Ali Mohamed Rage told a local radio station that the retreat was a tactical withdrawal and that there will be no pullout from southern Somalia, the area hardest hit by the famine.

"The retreat by our forces is only aiming to counterattack the enemy. People will hear happy news in the coming hours," Rage said. "We shall fight the enemy wherever they are." Residents reported Al-Shabab militia leaving their positions overnight but it was not clear if they had left the city. Since it was born from the ruins of another radical Islamist group in 2007, Al-Shabab has never abandoned Mogadishu entirely.

Mohammed Ali said he saw about 150 Al-Shabab fighters leaving the northwest part of the capital. He said they may have left town due to a lack of finances and disagreements between top leaders, explaining that he had an insight into the militia because "our brothers are on that side."

Lieutenant Colonel Paddy Ankunda, a spokesman for the 9,000-strong African Union peacekeeping forces in Mogadishu, said they are verifying the withdrawal reports.

Sodio Omar Hassan, who was seeking treatment for her child's malaria at a hospital set up by African Union peacekeepers, said people are angry at Al-Shabab's response to the relief effort. She said militia groups declined to grant the UN permission to distribute maize and cooking oil in a territory it controls.

"People are angry now they are dying," she said. "They (Al-Shabab) don't bring us anything." More than 12 million people in the Horn of Africa are in need of immediate food aid, but the crisis has been exacerbated by al-Shabab's unwillingness to allow many aid organisations into the areas it controls, saying it is better to starve than accept help from Western countries.

The UN says 640,000 children are acutely malnourished in Somalia, where the UN has declared five famine zones, including the refugee camps of Mogadishu.

Somalis who have fled the famine zones and reached Mogadishu told the Associated Press that militants are threatening refugees who leave the south, often stopping — and sometimes killing — the men, leading to a disproportionate number of women and children at camps for displaced people in the capital.

Somalia has been mired in war and anarchy for two decades, while piracy flourishes off its coastline. In a sign of how desperate the famine has become, many Somalis have fled from rural areas to Mogadishu, a war zone where AU peacekeepers battle Al-Shabab militants daily.