Photographer Edouard Elias and reporter Didier Francois, also from France, went missing on their way to the Syrian city of Aleppo, according to Reuters and other news sources.

French President Francois Hollande has called for their immediate release.

‘These are men who have worked so the world can get information… Journalists must be treated as journalists,’ Hollande said during a trip to Japan.

The pair work for Europe 1, a French radio station.