The French attacks on Islamist positions near the ancient desert trading towns of Timbuktu and Gao, the largest city in the north, marked a decisive intervention in area since Friday, containing the rebels' push towards the south, after they took control of Northern Mali in April.
France is determined to end Islamist domination of northern Mali, which many fear could act as a base for attacks on the West and for links with Al-Qaeda in Yemen, Somalia and North Africa.
French President François Hollande's intervention has won plaudits from leaders in Europe, Africa and the United States, but it is not without risks.
Commission President José Manuel Barroso welcomed the “courageous action of French troops” in Mali and voiced the will of the EU to “defend the integrity” of the country against the offensive of the armed Islamist groups.
“We are with you in this difficult moment and we support the courageous action of the French troops”, Barroso said in a speech in Marseille, at a ceremony launching Marseille Provence as the European Capital of Culture for 2013.
Hollande was not present, as he had to change his program because of the situation in Mali.
Defense Minister Jean-Yves Le Drian said France's sudden intervention on Friday had prevented the advancing rebels from seizing Bamako, the country's capital He vowed that air strikes would continue.
"The president is totally determined that we must eradicate these terrorists who threaten the security of Mali, our own country and Europe," he told French television.
Residents and rebel leaders have reported air raids early on Sunday in the towns of Lere and Douentza in central Mali, forcing Islamists to withdraw. As the day progressed, French jets struck targets further to the north, including near the town of Kidal, the epicenter of the rebellion.
In Gao, a dusty town on the banks of the Niger river where Islamists have imposed an extreme form of sharia law, residents said French jets pounded the airport and rebel positions. A huge cloud of black smoke rose from the militants' camp in the city's north, and pick-up trucks ferried dead and wounded to hospital.
Paris said four Rafale jets flew from France to strike rebel training camps, logistics depots and infrastructure around Gao with the aim of weakening the rebels and preventing them from returning southward.
"We blocked the terrorists' advance and from today what we've started to do is to destroy the terrorists' bases behind the front line," French Foreign Minister Laurent Fabius told LCI television.
France has deployed about 550 soldiers to Mali under "Operation Serval" -- named after an African wildcat -- split between Bamako and the town of Mopti, 500 km north.
In Bamako, a Reuters cameraman saw more than 100 French troops disembark on Sunday from a military cargo plane at the international airport, on the outskirts of the capital.
The city's streets were calm, with the sun streaking through the dusty air as the seasonal Harmattan wind blew from the Sahara. Many cars had French flags draped from the windows to celebrate Paris's intervention.
"We thank France for coming to our aid," said resident Mariam Sidibe. "We hope it continues till the north is free."
African troops expected
More than two decades of peaceful elections had earned Mali a reputation as a bulwark of democracy, but that image unraveled in a matter of weeks after a military coup in March which left a power vacuum for the Islamist rebellion.
France convened a U.N. Security Council meeting for Monday to discuss Mali.
France also raised the threat level for eight French hostages held by al Qaeda allies in the Sahara and for the 30,000 French expatriates living in neighboring, mostly Muslim states.
Concerned about reprisals, France has tightened security at public buildings and on public transport. It advised its 6,000 citizens to leave Mali as spokesmen for Ansar Dine and al Qaeda's north Africa wing AQIM promised to exact revenge.
In its first casualty of the campaign, Paris said a French pilot was killed on Friday when rebels shot down his helicopter.
Hours earlier, a French intelligence officer held hostage in Somalia by al Shabaab extremists linked to al Qaeda was killed in a failed commando raid to free him.
Hollande says France's aim is simply to support a mission by West African bloc ECOWAS to retake the north, as mandated by a U.N. Security Council resolution in December.
With Paris pressing West African nations to send their troops quickly, Ivory Coast President Alassane Ouattara, who holds the rotating ECOWAS chairmanship, kick-started the operation to deploy 3,300 African soldiers.
Ouattara, installed in power with French military backing in 2011, convened a summit of the 15-nation bloc for Saturday in Ivory Coast to discuss the mission.
"The troops will start arriving in Bamako today and tomorrow," said Ali Coulibaly, Ivory Coast's African Integration Minister. "They will be convoyed to the front."
The United States is considering sending a small number of unarmed surveillance drones to Mali as well as providing logistics support, a U.S. official told Reuters. Britain and Canada have also promised logistical support.
Former French colonies Senegal, Niger and Burkina Faso have all pledged to deploy 500 troops within days. In contrast, regional powerhouse Nigeria, due to lead the ECOWAS force, has suggested it would take time to train and equip the troops.
The December European Council approved a Crisis Management Concept for a Common Security and Defense Policy military mission to support the reorganisation and training of the Malian armed forces.