France's Defense Minister Jean-Yves Le Drian says a French helicopter pilot has been killed in combat against Islamist rebels in the west African state of Mali.
He did not say whether the pilot's helicopter had been shot down.
Le Drian said French warplanes have continued to launch air strikes against Islamist forces.
He said several hundred French troops are taking part in the operation and are protecting Mali's capital, Bamako.
Mali’s government has declared a nationwide state of emergency as it battles Islamist rebels in the north of the country, and has officially asked for French military assistance.
Reports say government and French forces have succeeded in driving back the Al-Qaeda-linked rebels from the central town of Konna.
In Washington, U.S. officials said the Pentagon is considering providing logistical, intelligence and other support to French forces involved in the fight.
Malian Interim President Dioncounda Traore on January 11 declared a state of emergency, and confirmed he had asked for air support from France, Mali’s former colonial power.
French President Francois Hollande said France could not allow what he called “aggression” by "terrorist groups, drug traffickers and extremists” to go unchallenged.
In his address on state-run television, Malian President Traore accused the rebels of trying to impose “a dictatorship from the Middle Ages reminiscent of obscurantism,” and called on all citizens to mobilize to counter the threat.
"The government of Mali has taken the decision to declare a state of emergency over the entirety of the national territory," Traore said. "Every Malian, woman and man, must consider themselves a soldier of the nation and act like one."
The crisis has arisen since a coup in March, 2012. In the wake of the instability, secular Tuareg rebels seized the north of Mali. The Islamists took advantage of the security vacuum to make their own power grab in the north.
This week’s seizure of Konna raised fears that the rebels were making a southward advance and would soon threaten other towns.
On January 10, the United Nations Security Council condemned the seizure of Konna and called on UN member states to assist Mali to reduce the threat posed by what it called “terrorist organizations and associated groups.”
The Security Council in December authorized an African-led force, supported by European states, to come to the aid of to Malian forces to recapture the vast northern region.
Officials say troops from Nigeria and Senegal have already arrived in Mali.
French Foreign Minister Laurent Fabius confirmed January 11 that French aircraft had carried out air strikes in support of the government.
Fabius accused the rebels of seeking to control the whole of Mali and implant what he called a “terrorist state” in the landlocked country of more than 14 million people.
In his remarks, French President Hollande maintained that France’s intervention would last for as long as necessary.
He said the situation was putting Mali’s continued existence in doubt.
"Mali is being confronted with an aggression, by terrorist elements coming from the north, the brutality and fanaticism of whom the entire world is aware of," Hollande said. "So today, the very existence of this state, which is a friend, Mali, the security of its population and that of our nationals, are being undermined."
U.S. State Department spokeswoman Victoria Nuland said Washington was in contact with France, but gave no specifics about what kind of assistance the U.S. might provide.
“We do understand that France has offered some immediate military support to the Malian armed forces at the request of the Malian government," said Nuland. "We are obviously consulting very closely with the government of France going forward."
With reporting by Reuters, AP, AFP and dpa