"We call on all of Mali's neighbouring countries to increase their border patrols to curb the flow of arms, drugs, fuel and fighters into Mali," Burns said on a visit to the country's northern neighbour Algeria.

"We applaud Algeria's resolve to stem the proliferation of weapons, drugs and fighters across the Sahel and strongly support these efforts," he said.

"We believe that an African-led multinational force supported by the international community may be necessary," he added.

The UN Security Council on Wednesday ordered sanctions against an Al-Qaeda linked group in a new sign of the tougher line being taken with militants who have taken over much of Mali.