Defense Secretary Leon Panetta has approved the request from Paris to provide French warplanes with mid-air refueling as French-led forces in Mali advance on the key northern city of Timbuktu. Saturday, they captured the key town of Gao and other towns from Al Qaeda and rebel forces. Many Islamists fled into desert hideouts and will be hard to hunt down. The Pentagon is also discussing widening US involvement in the French-led campaign to liberate northern Mali from Islamist extremist rule by helping to transport troops from other African countries including Chad and Togo. The French are preparing to hand over securing Gao to forces from Niger and Chad.