(Adds more Hollande quotes, army spokesman on troop numbers)
PARIS, Jan 28 (Reuters) - French President Francois Hollande said on Monday it would be up to African forces to tackle Islamist rebels in the northern part of Mali once the main towns in the region were retaken.
At a news conference in Paris, Hollande said "we are in the process of winning the battle" but acknowledged the harder part was still to come and that it would largely be a task for Malian and African forces.
After retaking several cities, including the northern town of Gao at the weekend, French and Malian troops sealed off the fabled desert town of Timbuktu on Monday after Islamists, who had taken control early last year, fled a French-led offensive.
Hollande said French troops would take a step back once the job of retaking key towns was complete.
"Then the Africans can take over the baton," Hollande said.
"They are the ones who will go into the northern part, which we know is the most difficult because that's where the terrorists are hiding."
In the face of a two-week-old French-Malian counter-attack, rebels have pulled back into the Saharan desert and mountains.
Military experts fear they could carry on a gruelling hit-and-run guerrilla war against the government from there.
Hollande sent French fighter jets to Mali on Jan. 11 and now have around 3,500 troops on the ground. There are a further 1,900 soldiers as part of the growing pan-African force.
As French and Malian troops push into northern Mali, African troops from a U.N.-backed continental intervention force expected to number 7,700 are being flown into the country.
"It's up to the Africans to permit Mali to restore its territorial integrity," Hollande told a news conference.
"Once territorial integrity is restored the French will only stay to train and direct. Just as we went into action rapidly, we will draw back to the starting points."
A third northern town, the Tuareg seat of Kidal, in Mali's rugged and remote northeast, remains in rebel hands. (Reporting By Brian Love, John Irish and Emmanuel Jarry; editing by Mark John)