During a visit to Washington, Le Drian said "terrorist groups are circulating across the whole Sahara-Sahel area and terrorist acts could put our own security at risk."
To confront the threat, "the partnership between France and the United States is indispensable" and has proven "fruitful" in recent months after French military interventions in Mali and the Central African Republic, he told an audience at a US think tank, the Center for Strategic and International Studies (CSIS).
In the French operation in Mali launched in January 2013, the Pentagon provided aerial refueling tankers, cargo aircraft and intelligence.
The Americans also have flown peacekeeping troops from Burundi and Rwanda to CAR, where a French contingent is working alongside an African Union force.
Reinforcing US-French cooperation in the restive Sahel region is the main theme of Le Drian's visit to Washington, where he is due to meet his counterpart, Chuck Hagel, as well as US intelligence chief James Clapper and President Barack Obama's national security adviser.
The partnership should be sustained both in the "operational domain but also in the domain of training" for African armies, Le Drian said.
The visit offers a chance for the minister to present to the Americans a French redeployment plan for the Sahel, which calls for 3,000 troops to be stationed at four hubs in Mali, Chad, Niger and Burkina Faso.
The Sahel area serves as a "highway for trafficking that poses a permanent threat, not only for Mali but also for the countries neighboring Libya, which for us is a source of concern," he said.
Some Islamist militants who fled Mali in early 2013 after the French operation have found refuge in southwest Libya.
The French military realignment in Africa is designed as a safeguard against "the risk of Libyan chaos," he said.
Washington is also worried about the situation in Libya -- where the government is struggling to assert its authority -- and plans to train 5,000 to 8,000 Libyan troops to bolster security on the country's borders.