PARIS -- Malian forces backed by French troops were advancing on Sunday toward the crucial northern town of Timbuktu as they began to deploy in the rebel stronghold of Gao, French officials said.
Prime Minister Jean-Marc Ayrault of France said in a statement that the French troops were "around Gao and soon near Timbuktu," farther west. Timbuktu has been under the control of rebels and Islamist fighters for 10 months, though there are reports that many of the Islamists have moved farther into the vast desert.
The French are also expected to move on to another large town, Kidal, with the notion of clearing population centers of the rebels and garrisoning them with allied African troops before the rainy season starts in March.
The capture of the main strategic points in Gao on Saturday represented the biggest prize yet in the battle to retake the northern half of Mali. The French Defense Ministry spokesman, Col. Thierry Burkhard, said Sunday morning on Europe 1 radio that troops from Mali, Nigeria and Chad were now deploying in Gao after French special forces took the city's airport and a strategic bridge on Saturday.
"The taking of control of Gao, which has between 50,000 and 60,000 inhabitants, by Malian, Chadian and Nigerian soldiers is under way," Colonel Burkhard said.
France had been pounding Gao with airstrikes since it joined the fight at Mali's request on Jan. 11. Gao, 600 miles northeast of Bamako, the capital, had been under the control of the Movement for Oneness and Jihad in West Africa, a splinter group of Al Qaeda in the Islamic Maghreb. Al Jazeera broadcast a statement from Al Qaeda in the Islamic Maghreb in which the group said it had withdrawn temporarily from some cities it held, but would return with a greater force.
In Washington, the Pentagon said Saturday that the United States would provide aerial refueling for French warplanes. The decision increases American involvement, which until now had consisted of transporting French troops and equipment and also providing intelligence, including satellite photographs.
France intervened after Konna was overrun by Islamic fighters on Jan. 10, and a clearer picture of the fighting has begun to emerge. Residents and officials said that at least 11 civilians had been killed in French airstrikes.
Charred husks of pickup trucks lined the road into the town, and broken tanks and guns littered the fish market, where the rebels had appeared to set up a temporary base.
Because of France's sudden entry into the fray, the United Nations and the Economic Community of West African States, the regional trade bloc known as Ecowas, have been scrambling to put together an African-led intervention force that has been in the planning stages. The Malian Army, which has struggled to fight the Islamist groups, has been accused of serious human rights violations.
It is easy to see why the Malian government pleaded for French help after the Islamist fighters took control of Konna. Just 35 miles of asphalt separate it from the garrison town of Sévaré, home to the second-biggest airfield in Mali and a vital strategic point for any foreign intervention force.
Residents said the town fell to the rebels when 300 pickup trucks of fighters, bristling with machine guns, rolled in and pushed back the Malian Army troops who had been guarding it after a fierce battle.
Amadou Traore, 29, a tire repairman, said residents had heard that the Islamist rebels had surrounded the town before the attack, but he had been confident that the army would keep them at bay.
"We thought there was no way for them to enter into the town," he said. "But they came in the night. They told us, 'Tomorrow we will go to Sévaré.' "
A woman who lived in his compound was hit by a bullet, he said. They tried to take her to the town clinic, but the doctor had fled. "After two days, she died," Mr. Traore said.
Baro Coulibaly fled her house along the main road into town, moving with her husband and six children to the relative safety of the town center, where they stayed with her in-laws for days. They heard French bombs and rebel bullets ricocheting around the mud-walled dwellings.
"Nobody could get in or out," Ms. Coulibaly said. "We were so afraid we barely ate or slept."
Residents said they heard that Iyad ag Ghali, the fearsome Tuareg leader of the Islamist group Ansar Dine, had led the attack, but no one saw him. The rebels spoke many languages, the residents said. Some were light-skinned Arabs and Tuaregs, a nomadic people, while others were dark-skinned people who spoke the languages of Niger, Nigeria and Mali.
Boubacar Diallo, a local political leader, said that only a few rebel fighters came at first. Later, hundreds more joined them, overwhelming the Malian soldiers based here. He said he never saw them pray and scoffed at their assertion that they would teach the Muslim population a purer form of Islam.
"They say they are Muslims, but I don't know any Muslim who does not pray," Mr. Diallo said.
The fighters took down the Malian flag and raised a banner of their own, a white piece of paper printed with words in Arabic -- "Assembly for the Spiritual Ideology to Purify the African World" -- and pictures of machine guns.
After the Islamist fighters fled, Mr. Diallo took it down and replaced it with the Malian flag.
Lydia Polgreen reported from Konna, and Steven Erlanger from Paris. Elisabeth Bumiller contributed reporting from Washington, and Scott Sayare from Paris.
This article originally appeared in The New York Times.