* Bombs hit Mogadishu, killing soldiers, children
* Relief agencies assess impact of al Shabaab ban
By Mohamed Ahmed
MOGADISHU, Nov 29 (Reuters) - A wave of roadside bombs in Somalia's capital killed seven people over two days, officials said on Tuesday, as government forces struggled to secure Mogadishu against attacks from Islamist rebels.
Al Qaeda-affiliated al Shabaab militants, fighting Somalia's Western-backed government, pulled out of most of their permanent bases in Mogadishu in August, and vowed to switch to guerilla tactics and target government installations.
Police and residents blamed al Shabaab fighters for the latest wave of blasts in the capital.
Analysts say local clan leaders and warlords have also moved in to take advantage of a security vacuum in Mogadishu, which government troops and African Union peacekeepers have failed to fill.
On Monday a roadside bomb killed two Somali soldiers and wounded three after it exploded near their car in northern Mogadishu, police officer Mohamed Abdullahi Omar told Reuters.
Another three soldiers were killed when they tried to disable roadside bombs in northern Mogadishu, police said, adding that two other bombs were found and disabled.
On Tuesday a bomb planted near a mosque in Bakara market killed two children, resident Mohamed Yusuf said.
"We have foiled and seized many others (roadside bombs) in the last few days," Somali police officer Adam Mohamed Ali told Reuters.
Residents said some al Shabaab fighters had pretended to renounce their allegiance to the rebels, only to melt into the population to launch attacks.
"We strongly believe that new al Shabaab defectors are behind the bombs being planted in the capital," Mogadishu resident Ibrahim Adam told Reuters.
"We know the defectors from the people but we can't talk about it because they are among us," he said.
Al Shabaab still occupy a few zones in Mogadishu and have carried out massive attacks that have killed dozens of people, leading critics to blame government forces and AU peacekeepers for failing to capitalise on the rebels' withdrawal.
"The threat of improvised explosive devices in Mogadishu remains real ... We ask people to remain vigilant in order to identify this new threat," AU peacekeeping spokesman Paddy Ankunda told Reuters.
AID GROUPS ASSESS BAN
The spate of roadside bomb attacks came as al Shabaab faced a concerted military campaign by Kenyan, Somali and Ethiopian troops to drive them out of the south and centre of the country.
On Monday, al Shabaab militants stormed and looted offices of aid agencies in southern and central Somalia, prompting the U.N. to say it was extremely concerned the disruption to humanitarian activities could bring back famine conditions in some regions.
The militants banned 16 aid groups, including U.N. relief agencies, from working in the country, at a time when a quarter of a million Somalis face starvation due to the worst drought in decades. Somalia's president condemned the ban.
"Yesterday in one nutrition stabilisation centre in Somalia, 15 children with the most severe form of malnutrition and medical complications were discharged," Marixie Mercado, spokeswoman for the U.N. Children's Fund, said in Geneva.
"These are obviously children at a very high risk of death," she added, without disclosing the location of the nutrition centre for security reasons.
The World Health Organisation said medical supplies were missing from their offices in Baidoa and Wajid and warned of shortages in supplies if access was not re-established soon.
Somalia has been mired in anarchy since warlords toppled military dictator Mohamed Siad Barre in 1991. (Additional reporting by Stephanie Nebehay in Geneva; Writing by Yara Bayoumy; Editing by Duncan Miriri and Andrew Heavens)