Somalia's government has declared a state of emergency in parts of the capital formerly controlled by the Islamist insurgent group, al-Shabab.

A decree from Somali President Sheik Sharif Sheikh Ahmed says clan militias are banned from what he called the “liberated” areas of Mogadishu.

The government is trying to exert authority in the former al-Shabab districts, amid worries that local warlords will instead seize control.

Al-Shabab pulled its fighters out of the Somali capital, Mogadishu, a little more than a week ago, following an offensive by government troops and African Union troops.

The government depends heavily on the AU soldiers to maintain control and order in the capital. The AU mission has called for more troops to bolster its current force of 9,000, comprised of soldiers from Uganda and Burundi.

On Saturday, the African Union said it had discovered a large cache of weapons left behind by al-Shabab.

An AU spokesman said troops found and destroyed 137 artillery shells in a neighborhood that was controlled by the militants.

Security forces have warned that al-Shabab may have also left behind bombs in the areas they abandoned.

The insurgent group once controlled nearly all of Mogadishu and still controls large sections of southern and central Somalia.

Its departure from Mogadishu has enabled the United Nations to scale up aid efforts to the drought and famine-stricken city. Al-Shabab has tightly controlled the delivery of aid to areas under its control, and has banned access for many international aid agencies.