BAMAKO, Mali (AP) -- After a punishing bombing campaign failed to halt the advance of al-Qaida-linked fighters, France pledged Tuesday to triple the size of its force in Mali, sending in hundreds more troops as it prepared for a land assault to dislodge the militants occupying the northern half of the country.

The move reversed France's earlier insistence on providing only aerial and logistical support for a military intervention led by African ground troops.

France plunged headfirst into the conflict in its former colony last week, bombarding the insurgents' training camps, arms depots and safe houses in an effort to shatter the Islamist domination of a region many fear could become a launching pad for terrorist attacks on the West and a magnet for extremists from around the world.

Despite five days of airstrikes the rebels have extended their reach, taking over a strategically important military camp in the central Malian town of Diabaly on Monday.

On Tuesday, France announced it was increasing the number of troops from 800 to 2,500. The offensive was to have been led by thousands of African troops pledged by Mali's neighbors, but they have yet to arrive, making it increasingly apparent that France will be leading the attack rather than playing a supporting role.

French President Francois Hollande told RFI radio early Tuesday that he believed France could succeed in ousting the extremists in a week. By afternoon he had outlined a far longer-term commitment. "We have one objective: To make sure that when we leave, when we end this intervention, there is security in Mali, legitimate leaders, an electoral process and the terrorists no longer threaten its territory," he said during a stop in the United Arab Emirates.

"We are confident about the speed with which we will be able to stop the aggressors," he added.

Supplies for the French forces arrived in a steady stream Tuesday, part of the enormous logistics operation needed to support thousands of troops in the baking Sahara sun, a terrain the Islamists have operated in for nearly a decade. Transport planes bringing military hardware landed in quick succession on the short airstrip: A giant Antonov, two C-17 Boeings and a C-160 disgorged equipment in preparation for a land offensive to try to seize back the northern territory held since April by a trio of rebel groups affiliated with al-Qaida.

Burly French troops in fatigues carried boxes of munitions as armored personnel carriers lined up at the airport's gasoline pump. Roughly 40 armored vehicles were driven in overnight by French soldiers stationed in Ivory Coast. They include the ERC-90, a six-wheeled vehicle mounted with a 90mm cannon. Dozens of French Marines camped out on the cement floor of an airport hangar.

Although at least 13 countries have offered support to the Mali mission, only France so far has boots on the ground. On Tuesday, U.S. Defense Secretary Leon Panetta reiterated the Obama administration's position, saying no American troops will be sent. The U.S. is helping with communications and intelligence-gathering, and may allow American aircraft to help with transport.

A convoy of French armored cars was spotted late Tuesday heading toward Diabaly, the strategic town seized by the Islamists a day earlier, said a resident of the nearby town of Segou, who declined to be named out of fears for her safety.

The Islamists appeared to be mostly equipped with Russian-made machine guns and other small arms, said a French Marine adjutant who gave only his first name, Nicolas, in keeping with military regulations. He added, however, that the French force would not underestimate the insurgents. On the first day of the operation, a French helicopter gunship was downed by rebel fire.

A French military spokesman said the Islamists had managed to seize more territory despite the air assault because the fighters were embedding themselves with the population, making it difficult to bomb without causing civilian casualties. He spoke on condition of anonymity in keeping with military protocol.

The French Mirage and Rafale fighter jets equipped with 550-pound (250-kilogram) laser- and GPS-guided bombs were useful for taking out convoys of rebel cars in the desert or militant complexes and warehouses away from urban centers, the spokesman said. They cannot be used to pinpoint rebels embedded with the local population.

Over the weekend, the rebels made their way to the rice-growing region, just north of the central Malian city of Segou, then seized Diabaly, a town of 35,000 that is home to an important military camp.

France ordered the evacuation of the roughly 60 French citizens living in the Segou region, then pounded the area around Diabaly with bombs all night Monday and again Tuesday, said Ibrahim Toure, a resident cowering inside a mud-walled home.

"They bombed the town all night long," said Toure. "I am hiding inside a house."

The Islamists taunted the French, saying they had vastly exaggerated their gains.

"I would advise France not to sing their victory song too quickly. They managed to leave Afghanistan. They will never leave Mali," said Oumar Ould Hamaha, a commander of the Movement for Oneness and Jihad in West Africa, an extremist groups whose fighters are believed to be in Diabaly.

"The French resemble a fly that was attracted to a pot of honey. Now their feet are sticky. They can't fly away anymore. ... It's to our advantage that they send in French troops on foot. We are waiting for them. And what they should know is that every French soldier that comes into our territory should make sure to prepare his will beforehand, because he will not leave alive."

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Associated Press writers Cassandra Vinograd in London and Lori Hinnant, Elaine Ganley and Sylvie Corbet in Paris contributed to this report.