The Central African president on Wednesday ordered warlords from his former rebellion to give up their fiefdoms in the capital Bangui and African troops moved in to subdue recalcitrant armed groups.

One of the most substantial efforts to restore order since a March coup came a day after French President Francois Hollande said urgent action was needed to prevent the Central African Republic from becoming a failed state.

The country's new strongman, head of the former rebel group Seleka Michel Djotodia, stripped his movement's unruly fighters -- who have been accused of rape, executions and looting -- of any security responsibilities.

"As of today, only the police and gendarmerie are mandated to take action on anything related to restoring and maintaining order," Security Minister Josue Binoua said after a security cabinet meeting chaired by Djotodia.

"In all modern countries, security is the task of the police and gendarmerie. The army looks after the defence of the territory," he said on state radio.

Moments earlier, Djotodia had ordered Seleka forces based in the northern Bangui neighbourhood of Boy-Rabe to return to their bases and allow the police and gendarmes to move in.

Regular forces attempting to take over from Seleka militia bosses were also backed by troops from the African Union's International Support Mission to Central Africa (MISCA).

Boy-Rabe is considered a stronghold of supporters of Francois Bozize, the ex-president who was ousted by the Seleka coup in March after 10 years in power.

Sporadic exchanges of fire which hospital sources said killed two people erupted there on Monday night, sending many residents fleeing to other Bangui neighbourhoods.

In the adjacent district of Boeing, nearly a thousand people fleeing the fighting and looting found refuge on Bangui airport's runways, an airport official said on condition of anonymity.

At least two flights were delayed by the runway invasion, the source added, one an Air Maroc aeroplane and another belonging to Air France.

Djotodia's coup was met with muted international criticism and the former rebel boss was eventually sworn in as president earlier this month with the task of leading the country to elections within 18 months.

Hollande called on the United Nations and African Union to "take charge of the situation" in the violence-wracked Central African Republic in a speech on Tuesday, and said it was "more than time to act" in the former French colony.

He warned against the "Somalisation" of the impoverished landlocked country, in reference to the lawless Horn of Africa country of Somalia for which the term "failed state" was coined.

Central Africa has been beset by reports of widespread rape, recruitment of child soldiers, weapons proliferation, huge population displacement and severe malnutrition since the coup in March.

Since taking power, Djotodia has emphasised his wish to disarm his former rebel supporters and a motley crew of armed groups that he had surrounded himself with before taking power, but has so far been unsuccessful.

Seleka -- which means "alliance" in the local Sango language -- counts approximately 25,000 combatants, but many obey only their immediate superiors.

Deputy Commissioner for Peace and Security of the African Union, El Ghassim Wane, said the body was "working to establish institutions", but its Central African force currently has just 750 men -- of a projected 3,652 -- due in part to funding problems.

Rights groups and observers say the new administration -- a broad unity government -- wields no influence whatsoever outside Bangui, leaving the rest of the country prey to marauding Seleka forces.

The landlocked nation has 4.6 million inhabitants scattered over a territory larger than former colonial power France, replete with untapped mineral wealth and bordering other chronically unstable countries such as DR Congo, Chad and South Sudan.