The United States has agreed to refuel French fighter jets waging war against Islamist militants in Mali, officials said Saturday, after weighing the decision for more than two weeks.

Defense Secretary Leon Panetta told his French counterpart, Jean-Yves Le Drian, in a phone conversation Saturday the Pentagon was ready to offer its vast fleet of aerial refueling tankers to back up French forces in Mali, spokesman George Little said in a statement.

Panetta and Le Drian discussed US military support "to deny terrorists a safe haven in Mali," he said.

"Secretary Panetta informed Minister Le Drian that US Africa Command will support the French military by conducting aerial refueling missions as operations in Mali continue," Little said.

They also discussed plans for the Americans to transport troops from African nations, including Chad and Togo, to support the international effort in Mali, he added.

President Barack Obama's administration has endorsed the French intervention and previously agreed to share intelligence and to provide transport aircraft. But Washington had hesitated on committing to refueling.

US officials, who spoke on condition of anonymity, had said the administration wanted to carefully consider the move and to review the objectives of the French operation, amid concerns of being drawn into an open-ended conflict.

The US military has an unparalleled fleet of more than 400 tankers equipped to refuel fighters and other warplanes in mid-air, while France has about 14 tankers.

Panetta's talks came a day after Obama spoke by phone with French President Francois Hollande, with the two vowing to work together to tackle extremism across North Africa.

France deployed troops to Mali two weeks ago that have been working with government forces to try to flush out radical Islamist fighters including Al-Qaeda linked rebels who had seized control of several northern towns.

French-led troops on Saturday recaptured the Islamist stronghold of Gao in what was seen as a major boost to the 16-day-old offensive against the rebels who are holding Mali's vast desert north.

French Prime Minister Jean-Marc Ayrault said the nation's troops also were advancing on Timbuktu, another key northern town held by the insurgents.