Troops mount foot patrols in Gao after surprise attack

Troops focused their attention on the Niger River, which jihadists used as a landing point for an attack on Sunday.

French troops were also patrolling Gao despite earlier insisting they would hand over control of the city to African forces.

Sunday's attack and two suicide bombings have showed that the fighters who once held the town still present a threat.

While neither suicide bomber killed other people, the attacks have raised fears that jihadists could be preparing to stage more assaults on civilian centres in northern Mali.

French President Francois Hollande said his goal was that "not one space of Mali's territory be under the control of terrorists.

"The essential part of the Malian territory is today liberated, but we haven't finished our task," he said.

"There are still terrorist pockets, notably in the extreme north of Mali, and operations are still being conducted by a certain number of groups."

He spoke as Amnesty International marked International Day against the Use of Child Soldiers today by revealing the shocking extent of young boys being used as combatants in Mali.

The jihadists who took control of northern Mali used children as young as 10, Amnesty said.

"These children were carrying rifles. One of them was so small that his rifle was sometimes dragging on the ground," one eyewitness said.

One captured child soldier told Amnesty he had been sold to jihadists where he was made to work in the kitchen where they were beaten when they mispronounced Arabic.

They were then trained to fight.

The boy said four child soliders were killed when Malian and French troops retook Diabaly in late January.

Amnesty said it also had evidence that government-backed militias had recruited child soldiers, but said there was currently no documented case of them being used in battle.

It is a war crime to conscript or use child soldiers under age 15 in active hostilities.

Amnesty called on states to sign up to a strong arms trade treaty that would ban arms sales to countries using child soldiers.