WASHINGTON (AFP) - US President Barack Obama on Monday put the price of United States (US) logistical support for France and Chad in the campaign against insurgents in Mali at up to US$50 million (S$62 million).

Washington has been providing airlift and air refueling services to France and lifting Chadian troops in transport planes in the month-long operation.

In a message to the Pentagon, Obama directed that the money be used to finance "efforts to secure Mali from terrorists and violent extremists".

A White House official said that France would continue to pay the US for fuel that it provides for French aircraft in the operation.

Washington has not made a direct military intervention in the conflict.

Last week, vice-president Joe Biden hailed France's "decisive" intervention in Mali and joined French President Francois Hollande in calling for United Nations (UN) peacekeepers to be quickly deployed to the country.

Biden also praised France's "decisiveness" in intervening in Mali and the "competence and capability" of French military forces, which drove militants from key northern cities they had seized last year.

France was responding to a cry for help from Mali's interim government and deployed fighter jets, attack helicopters and ground troops.

But a turn to suicide attacks, landmine explosions and guerrilla fighting reflect the deep problems facing Mali, and France is now eager to wind down the operation and hand over to a UN peacekeeping mission.