French airstrikes in Mali's key northern town of Konna have driven back Islamist militants who had captured the town earlier this week.

Officials said Saturday that French forces had pushed rebels from Konna. The Islamists' takeover of the town had placed the militants within 25 kilometers of Mopti, the northernmost city under Malian government control.

The French News Agency says dozens of Islamist fighters have been killed in the operation. Also, France's defense minister said Saturday a helicopter pilot was killed during the air strikes, which began Friday.

Meanwhile, French Prime Minister Jean-Marc Ayrault said French forces are preparing for any rebel surge on the Malian capital, Bamako. He said troops will remain in the area as long as necessary, saying the militants are behind much lawlessness, including kidnappings.

France announced Friday that it had deployed troops to Mali at the request of the government. Troops from Nigeria and Senegal are also reported to be in Mali to help government forces.

In another development Saturday, African officials said, ECOWAS, the West African regional block had authorized the immediate deployment of troops to Mali.

In December, the U.N. Security Council approved a plan for West African states to deploy at least 3,000 troops to Mali to help train the army and retake the north. But originally, no troops had been expected in Mali until September.

France's Foreign Ministry has advised French citizens in Mali to leave the country “temporarily,” while the U.S. embassy in Bamako is urging Americans against all travel to the West African country.

Al-Qaida-linked groups took control of Mali's north soon after renegade soldiers overthrew the country's elected president last March. The groups have imposed a harsh form of Islamic law on the areas in their control, drawing condemnation from human rights groups.

Mali's interim president, Dioncounda Traore, declared a national state of emergency Friday and called on every Malian to help in the war effort.

“Every Malian, man and woman, should from here on out consider oneself to be a soldier of the nation and behave as such. We call on all mining, telephone and other companies, as well as all people morally and physically able, to contribute to this fight against terrorism. All public services should put all vehicles that could be useful in the field at the service of the army without delay.”

French President Francois Hollande said the French forces are helping to fight what he called “terrorist elements” in Mali.

“This operation will last as long as necessary. I will keep the French regularly informed about its proceedings. The terrorists must know that France will always be here, when it comes to not only its fundamental interests but also the rights of a population, that of Mali, which wants to live freely and in a democracy.''

Mali's president had asked France, the country's former colonial ruler, for immediate help in stopping the rebel advance. Diplomatic sources say Mr. Traore will meet with President Hollande in Paris next Wednesday.

On Thursday, the government ordered all schools closed in the capital and the nearby garrison town of Kati, citing the threat of civil unrest.

The order, which covers kindergarten through university, came as state television broadcast a statement saying in part that the country faces “one of the direst periods in its history.” It urged all citizens “to unite behind the army in the fight to take back the north.”