US President Barack Obama directed nearly 7,500 million euros (10 million dollars) to bolster a major French counterterrorism mission in Africa's Sahel region.
"I hereby determine that an unforeseen emergency exists that requires immediate military assistance to France in its efforts to secure Mali, Niger and Chad from terrorists and violent extremists," Obama said.
The funds will be used to help France with airlift and aerial refuelling services, according to National Security Council spokesman Edward Price.
France recently overhauled its mission in Mali, launched in January 2013 to push out Islamic radicals, to involve more countries along the southern rim of the Sahara that are affected by terrorist activity.
Renamed "Operation Barkhane", the mission will dispatch some 3,000 French troops spread out across Mauritania, Burkina Faso, Niger, Chad, and Mali and will be backed by aircraft and logistical support from the United States and some EU countries.