BAMAKO (Reuters) -A Colombian nun who was kidnapped in 2017 by Islamist militants in Mali has been freed, Mali's presidency said on Saturday.

       Gloria Cecilia Narvaez was kidnapped by the Macina Liberation Front, an al Qaeda-linked group, in February 2017 near the border with Burkina Faso.

       "The presidency of Mali salutes the courage and bravery of the nun. This liberation is the crowning achievement of four years and eight months of combined efforts by several intelligence services," the presidency said in a statement.

       Photos posted on the presidency's Twitter feed showed Narvaez, smiling and dressed in a yellow robe and headscarf, meeting with Mali's interim President Assimi Goita.

       Kidnapping has been a lucrative source of cash for Islamist groups in West Africa's Sahel region, where they are waging an expanding insurgency against national armies, French forces and U.N. peacekeepers.

       The presidency did not say whether any ransom had been paid for Narvaez.

       (Reporting by Paul Lorgerie in Bamako, Editing by Rosalba O'Brien)