KIDAL, Mali (Reuters) - Mali will release scores of suspected Islamist insurgents in a prisoner exchange for opposition leader Soumaila Cisse and French aid worker Sophie Petronin, two security sources and a diplomatic source said on Monday. Cisse, a popular politician who served as finance minister from 1993 to 2000, was kidnapped by gunmen while campaigning in the northern region of Timbuktu in March, while Petronin, who ran a charity for malnourished and orphaned children, was abducted near the northern city of Gao in late 2016. They are two high-profile examples of Mali’s deepening security crisis caused by the persistent presence of jihadist groups bent on overthrowing state authority, despite the intervention of thousands of international troops and the arrest of scores of suspected insurgents. Multiple planeloads of prisoners have been flown to the town of Tessalit in northeast Mali, one regional and one Mali-based source said on condition of anonymity. The release of Petronin and Cisse was secured when authorities agreed to free a large number of detained suspected militants, the sources said. It was not clear how many prisoners are set to be released, but one plane brought 70 to Tessalit on Sunday, the Mali-based source said. Authorities were not available for comment in Mali, where groups with links to al Qaeda and Islamic State stage frequent deadly attacks on civilian and military targets in central and northern regions, and use the area as a base from which to carry out strikes in neighbouring Niger and Burkina Faso. A military coup that overthrew President Ibrahim Boubacar Keita in August has magnified concerns among regional leaders about the spread of violence in West Africa’s Sahel region. France’s foreign ministry declined to comment on Monday. Representatives for the hostages could not be reached to confirm if they had been freed.