The United States is significantly expanding its assistance to a French assault on Islamist militants in Mali by offering aerial refueling and planes to transport soldiers from other African nations, the Pentagon announced Saturday night.

The gesture comes amid a debate within the Obama administration about how deeply it should engage in the French effort to prevent Islamists from wresting control of the West African nation. French requests for more robust support from Washington raised a legal dilemma because U.S. law forbids foreign assistance funds to leaders that came to power through a coup. Mali’s military leaders, including some trained by U.S. troops, seized power last year by force.

“The French requested this support, and we believe it was important to move ahead,” a senior defense official said Saturday night, speaking on the condition of anonymity to discuss policy deliberations. “The U.S. has the most advanced refueling technology in the world, and we wanted to provide this support.”

The United States has concluded that the expanded assistance is legally sound because of France’s notification to the United Nations Security Council that its mission in Mali is being offered at the request of the African country’s government, which is fighting “terrorist elements,” Pentagon spokesman Lt. Col. James Gregory said in a statement.

“Under these circumstances, the U.S. can lawfully provide support to France’s efforts in the armed conflict in Mali,” Gregory said. Gregory said the coup bars “foreign assistance funds,” not military support.

A look at the events leading up to the intervention in Mali.

“We remain mindful of, and are carefully taking into account, the coup restrictions as our plans for assistance develop,” he added.

The Pentagon made the announcement after Defense Secretary Leon E. Panetta spoke to his French counterpart, Jean-Yves Le Drian, on Saturday about the conflict in Mali, Pentagon spokesman George Little said. Their call followed one Friday between President Obama and French President Francois Hollande.

During the Saturday call, Panetta commended France’s offensive and “noted recent operational successes that have helped turn back terrorist advances,” Little said, according to a statement the Pentagon issued summarizing the call. The statement said that besides offering aerial refueling, which will enhance France’s ability to bomb suspected Islamist cells, Panetta offered to make U.S. military aircraft available to ferry allied soldiers from African nations including Chad and Togo to “support the international effort in Mali.”

France deployed troops to Mali on Jan. 11, fearing that rebel militants could be close to seizing control of the capital, Bamako. The landlocked country, home to 14.5 million people, is a former French colony and remains an important trade partner for Paris. U.S. officials have watched Mali’s turmoil with great concern, fearing that large, strategically important regions of the African country could become havens for hard-line Islamist militants with global terrorist aspirations.

As French troops descended on the Malian capital, some French officials held out hope that the United States and Britain would provide significant support. London and Washington have endorsed the offensive, but the two allies have only pledged nonlethal support, mainly transport planes.