In a message of condolence on Saturday, Ayatollah Khamenei voiced sympathy with bereaved familites of the victims.
The Leader underlined that youth should be protected, and asked military and civil officials to carefully pursue all necessary measures to prevent similar incidents.
Earlier, Iranian President Hassan Rouhani offered a message of condolence on the death of 19 soldiers in a bus accident south of the country, and ordered his ministers to make whatever efforts possible to address the problems of the injured and their families.
In the early hours of Wednesday, a bus carrying soldiers rolled over on a road linking the southern cities of Shiraz and Kerman, killing 19 passengers and injuring 23 others.