Four people were killed on Wednesday in a drone attack in eastern Syria, in an area held by pro-Iranian groups, the Syrian Observatory for Human Rights (SOHR) reported. "Four people were killed and eight injured in a drone strike carried out near an arms factory belonging to pro-Iranian groups and near a truck loaded with weapons," in the Deir Ezzor region, Rami Abdel Rahmane, director of the SOHR, told AFP.