BERLIN—Germany has organized the return of three women and 12 children from camps in northeastern Syria for humanitarian reasons, its foreign minister reported on Sunday. Heiko Maas did not further identify the women or children, who were flown back to Germany on Saturday. However, the German weekly Bild am Sonntag reported that all three women had left Germany in recent years to join the extremist ​ISIS​ terrorist group in Syria. The paper identified the women as Merve A., Yasmin A. and Leonora M. Also Sunday, Germany’s federal prosecutor’s office said a German citizen by the name of Leonora M. had been arrested upon her arrival at Frankfurt airport. It said she is accused of membership in the foreign terrorist group ISIS and allegedly committed crimes against humanity. Maas said he was “very relieved” about the return of the 12 children and three of their mothers. He said the return was organized …