The incident happened when the passenger bus overturned on a highway in the Western outskirts of the capital.
"7 people were killed and 10 more have been wounded, including 5 who are in critical conditions," Managing-Director of Tehran and the Countryside Bus Driving Company Peiman Sanandaji told FNA this afternoon.
Noting that the bus was driving below the speed limit, he said "the incident has most likely been the result of a technical fault".
Sanandaji said that investigations are underway into the cause of the incident.