Sprinting through the bombed out buildings in Somalia's famine-stricken capital, gunmen chase a man suspected of belonging to Al-Qaeda-linked Shebab rebels.

"That one! No, the other man!" the commander shouts, as his heavily armed troops charge down the pot-holed street, AK-47 automatic rifles levelled at the suspect.

In a dangerous city ravaged by war between rival factions for two decades -- this section was wrested from Shebab fighters by a pro-government militia called Ahlu Sunna Waljama two months ago -- nobody seems to trust each other.

Curious children peer out over a broken balcony, and women scurry back into narrow alleyways as screaming gunmen surround the suspect.

"Bring him here!" the commander shouts, standing at his base, a ruined building with sandbags piled in smashed windows for machine gun emplacements, a ragged Somali flag fluttering outside in the warm sea breeze.

This time it is a case of mistaken identity, and the man is released, shaken but unharmed.

Shebab forces withdrew from Mogadishu positions earlier this month after years of battles, but African Union troops have warned the rebels are preparing terrorist or guerrilla style attacks.

"We are protecting our people," said Abullahi Moalim, a commander in Ahlu Sunna -- meaning "the majority" -- who oppose the hardline Islamist Shebab, following instead Somalia's traditional moderate Sufi version of Islam.

"We drove the Shebab out of this area," Moalim added, speaking with a thick American accent -- he grew up in Kansas, before returning to his birth nation to fight in the Ahlu Sunna.

This area, the Hodan district, was one of the hardest fought over areas in the war-racked capital, a former Shebab stronghold adjoining a key road connecting the airport and presidential palace, held by AU-backed forces.

Both sides smashed holes between buildings to allow easier movement out of sight of sniper fire, while Shebab fighters dug extensive tunnel networks under the roads, with hidden holes they used to pop up as surprise firing points.

"It took us ten months to push the Shebab out," said Haj Kuwait, the nom du guerre of an Ahlu Sunna fighter, one of reportedly several hundred in this part of the city.

"They fought us in every street, every house, every day," he said, waving at his house, an apartment block, where two sides are punctured with gaping holes smashed by mortar rounds.

Both sides used heavy machine guns mounted on pickup trucks to dislodge each others positions, and piles of bullet casings lie in regular piles, each mound representing several hundred dollars worth of ammunition.

"The fighting went on day after day, even RPGs (rocket-propelled grenades) did not drive them out from positions, they were very determined," Kuwait added.

Peeling pastel-coloured paint left on crumbling walls of Italian colonial era villas provide a small hint of how this once elegant city -- situated beside the rolling waves of the Indian Ocean -- must have looked before the war.

Cactus plants now sprout out of an open-air cinema, while a theatre is reduced to rubble. Purple bougainvillea plants once grown in gardens now curl over a smashed triumphal monument to long forgotten colonial heroes.

Over 100,000 people have fled into Mogadishu in recent months fleeing extreme drought, which has escalated into famine in several areas, including inside the capital.

Several thousand people are packed into makeshift tent camps in Hodan, living in ragged tents made of plastic sheeting and scraps of material.

"Security is alright," said Ibrahim Madey, who fled famine-struck Lower Shabelle region, watched warily by a gunman, carrying a machinegun and draped in belts of bullets.

"But all my children are sick with diarrhoea, and my baby has measles," he added.

Beside a small mosque destroyed by the fighting, with chunks of masonry ripped from its minaret, new arrivals are putting up basic shelters. Regular crackles of gunfire still ring out.

Residents seem to welcome the gunmen patrol the streets, as long as their families can get enough to eat and are protected.

"Our fears are not about the Shebab now, but about feeding my children," said Huwa Ibrahim, a mother of four.