Washington is determined to prevent north African armed jihadist group Al-Qaeda in the Islamic Maghreb (AQIM) setting up a base in Mali, and is discussing with France how it can support its efforts, he said.
"With regards to the nature of the assistance that we would provide we are in discussions with the French," he said in Madrid after meeting Spanish Defence Minister Pedro Morenes.
"We are discussing in Washington some of the requests that have been made to determine exactly what assistance we can provide," he added, speaking on the second stop of a European tour.
Morenes said Spain was letting French planes overfly its maritime airspace on their way to their operations in Mali.
Panetta said earlier in Lisbon: "Our commitment ever since 9-11 has been to go after Al-Qaeda wherever they are and to make sure that they have no place to hide," in comments after talks with his Portuguese counterpart Jose Aguiar-Branco.
"Our hope is that we can work with the French to provide whatever assistance we can to try to assist them in that effort," he added. "The hope is that, ultimately, they will be able to succeed and establish better security for Mali."
But Panetta, who said Monday the United States could offer intelligence and logistical support, stressed that there was no question of sending US ground forces into battle in Mali.
"There is no consideration of putting any American boots on the ground at this time," he said.
France launched a campaign of air bombardments Friday to halt an advance on the Malian capital Bamako by Islamist fighters. A contingent of 750 French troops has been sent to bolster Malian forces against the rebels, who have controlled northern Mali since April.
"Al-Qaeda still remains a threat and they have relocated in other parts of the world," Panetta said, claiming success in weakening the network in Yemen and Somalia.
"The job is not finished. We have to continue the effort to go after Al-Qaeda where it decides to relocate."
Panetta was due to travel on to Italy before heading to Britain on his final foreign tour as Pentagon chief.