Two people have been arrested after a university bus in Iran lost control, collided with column, killing 10 people and leaving 25 students injured.
Prosecutors announced on Wednesday that a manager of the company that leased the bus and a university official have been detained.
The bus was carrying 30 students along a mountainous road within the science research campus of Islamic Azad University in northwestern Tehran when it came off the road and hit a concrete column on Tuesday.
25 students were injured in the accident and several are in serious condition, raising the possibility of the death toll rising.
Seven were killed instantly, state TV said, while an updated death toll of 10 was reported by Tasnim the day after the crash.
Iran was the world's seventh deadliest country for drivers per capita, according to the World Health Organization's latest figures from 2013, and the only non-African country apart from Thailand in the top 10.
Iranian authorities say over 16,000 died on the road in the last Iranian year (2017-18).
Efforts to modernize Iran's ageing and highly polluting cars have been hampered by a lack of investment, and foreign companies such as Peugeot and Renault were again forced to withdraw this year by the return of U.S. sanctions.
The university blamed Tuesday's crash on the driver having a stroke, but many on social media pointed to its ageing bus fleet and lack of road maintenance. The drivers remains have been sent to autopsy and the result will be clear in a few weeks, officials said.
Journalist Mahmoud Sadri tweeted that the university's use of a "ramshackle bus in a mountainous region" amounted to "manslaughter".
Supreme leader Ayatollah Ali Khamenei offered his condolences over the "tragic accident" in a statement on Tuesday.