Though its troops are posted in locations around Africa, French leaders earlier said they wouldn't send combat troops to Mali and that they'd scale back France's military interventions on the continent.

So its decision to get involved in Mali, an operation Hollande said "will last as long as necessary," underlies the seriousness of France's concern about the situation there. French hostages have been taken in neighboring Niger by al Qaeda in the Islamic Maghreb, and Paris appears intent on containing any further militant expansion in the heart of Africa.

"The terrorists' breakthrough must be stopped," said French Foreign Minister Laurent Fabius, justifying France's efforts "to train and reshape the Malian army." "If not, (all of) Mali falls into their hands, with a threat to the whole of Africa and Europe."

The U.N. Security Council last month authorized a one-year military peacekeeping mission in the country. ECOWAS members pledged thousands of troops, and the Security Council has urged other nations to contribute forces as well.

Hollande spoke Saturday evening with British Prime Minister David Cameron, who consented for the United Kingdom to "provide logistical military assistance to help transport foreign troops and equipment quickly to Mali" -- but no "British personnel in a combat role" -- a Downing Street spokesman said.

France has been in contact with U.S. Defense Secretary Leon Panetta about the situation, as well as its African and European allies, according to Le Drian.

The U.S. military is weighing its options -- which could include logistical support and intelligence sharing with France -- said a U.S. defense official, who declined to be named because no decisions have been made.

"This is a serious issue, and ... the United States is committed to going after terrorists wherever they may be in order to protect American interests, but also those of our partners and allies around the world," Pentagon spokesman George Little said this week.