"Alvaro Leyva Duran will be our minister of foreign affairs. It will be a chancellery of peace," Petro tweeted, adding that Colombia will focus its efforts on overcoming the climate crisis and ending endemic violence.
Leyva Duran, 79, has served as a mines and energy minister, a congressman from the Conservative Party, and a mediator in the country's peace process, among other positions.
He played a major role in building the justice model of the Special Jurisdiction for Peace, which was created within the peace agreement signed between the Colombian government and the former guerrilla movement of Revolutionary Armed Forces of Colombia in 2016.
Besides Leyva Duran, Petro has appointed his vice president Francia Marquez to create a Ministry of Equality.