French troops may start pulling out of their anti-extremist operation in Mali as early as next month, handing over to a still-developing African force.

The potential pending withdrawal, floated by French Foreign Minister Laurent Fabius in a newspaper interview published Tuesday night, came as forces from France and Chad secured a key bastion in northern Mali, the city of Kidal.

French aircraft and troops also are targeting suspected hideouts of Islamist fighters in the sparsely populated Saharan desert. There are fears that the extremists who have fled Mali's cities during the three-week French-led operation could try to stage attacks from remote bases.

The French foreign minister is quoted in France's Metro newspaper as saying, "I think that starting in March, if everything goes as planned, the number of our troops should diminish."

Fabius, whose office tweeted the newspaper story, stressed that terrorist threats remain and that the fight isn't over yet, but that ultimately Africans and Malians themselves need to take responsibility for the region's security.

France has some 4,000 troops in Mali as of Tuesday, a French military official said. That's about the same number as France had at the height of its 11-year military presence in Afghanistan.

France launched the Mali operation last month to drive back al-Qaida-linked extremists who had seized the north of the country, imposing harsh rule on local populations, and had started pushing toward Mali's capital. France's government fears the region could become a haven for international terrorists.

A U.N. diplomat said Tuesday that the French are talking about another month or so of active engagement in Mali, with one aim being the interruption of supplies to the extremists.

The U.N. Security Council is likely to wait until the end of February, when the military action has hopefully ended, to adopt a new resolution authorizing a U.N. peacekeeping force for Mali, the diplomat said. The diplomat spoke on condition of anonymity because of the sensitivity of the Mali conflict.

As French troops focus farther north, they are moving out of cities they seized earlier in the operation. They are already expected to start handing control of the fabled city of Timbuktu to African forces this week. Extremists had overtaken Timbuktu last year; French forces pushed them out last month and French President Francois Hollande arrived in the city to accolades from its residents.

Some 3,800 forces from other African states are in Mali backing up the weak Malian army, the official said. But it is far from clear that the African forces are ready to take full responsibility against the Islamic extremists, who may strike the cities from their desert hideouts.

The spokesman for the Malian military in Timbuktu, Capt. Samba Coulibaly, said there is no reason for the population to fear the withdrawal of French troops.

"With the size of the force we have here right now, we can maintain security in the town of Timbuktu," he said. "The departure of the French soldiers does not scare us, especially since their air force will still be present both in Timbuktu and Sevare. They control this entire zone and can intervene within a matter of minutes in order to carry out airstrikes as needed," he said.

Some 1,800 Chadian troops are now holding the northern city of Kidal, the French military official said Tuesday.

The French last week began a campaign of airstrikes on Islamic rebel outposts around Kidal and Tessalit. French Mirage and Rafale fighter jets have flown 135 sorties since Thursday and targeted 25 sites, primarily fuel and logistics depots, the French Defense Ministry said.

While their forces took control of Kidal's airport some time ago, it's not clear why they did not take Kidal city with the same swiftness as they took Gao and Timbuktu.

There was speculation that the pace of their advance was being constrained by the fact that the retreating rebels are holding Western hostages, including eight who are French. Fears have mounted about their safety as the French intervention has moved closer to where several of them are thought to be held.

In a sign of normalcy, the mayor's office of Timbuktu announced that they will open for the first time in 10 months on Wednesday, said the city's mayor, Ousmane Halle.

Government officials will tackle "the most important needs first," he said. "Including garbage removal and issuing birth certificates for the children born since the Islamists took over."

"The city is now secure. There are ongoing patrols by French and Malian soldiers, and we no longer have any reason to fear an attack by the Islamists," he said.

However, the conflict may go on for a long time, warned a high-ranking Algerian security official, based in the vast Sahara bordering Mali.

"The war risks being long and the terrorist groups could use the same strategy used by al-Qaida in Afghanistan against U.S. forces, notably suicide attacks and surprise attacks targeting French and Malian troops," said the security officer, who refused to give his name because the sensitivity of the subject. "While the French and Malian forces easily chased the terrorists out of the Malian cities like Gao and Kidal, it will be more difficult for them to dislodge them from the mountains in the north of Mali."

Meanwhile, secular rebels from Mali's Tuareg group say they have arrested two Islamic extremists, including the man blamed for enforcing stoning deaths and amputations in Timbuktu.

A statement from the National Movement for the Liberation of Azawad on Monday said Mohamed Moussa Ag Mohamed of Ansar Dine and Oumeini Ould Baba Akhmed of the Movement for Unity and Oneness of the Jihad, or MUJAO, were arrested Saturday near Mali's border with Algeria.

The NMLA launched a rebellion last year and seized most of northern Mali. They initially fought alongside Ansar Dine and MUJAO but they soon hijacked the Tuareg nationalist uprising.

The NMLA said the two men have been interrogated and information shared with French troops who are leading a military intervention in Mali. It said the men are in Kidal. The claims of these arrests, however, could not be immediately confirmed.

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Charlton reported from Paris. Associated Press reporters Edith Lederer in the United Nations, Michelle Faul in Johannesburg and Aomar Ouali in Algiers, Algeria contributed.