The report said the number of casualties could rise, though initial details about the disaster involving a train reportedly carrying some 350 passengers remained unclear.
Four of the seven cars in the train derailed in the early morning darkness near the desert city of Tabas, Iranian state television reported. Tabas is some 550 kilometers (340 miles) southeast of the capital, Tehran.
Rescue teams with ambulances and helicopters had arrived in the remote area where communication is poor. Over a dozen people suffered critical injuries, with some transferred to local hospitals, officials said.
Iranian media quoted the governor of Tabas, Ali Akbar Rahimi, as saying the crash killed at least 17 people and that the number of fatalities may rise as rescuers search the train cars.