At least 21 people have been killed after a bus overturned in the south of Iran, state media has reported.

Masoud Abed, the head of Fars province’s emergency organisation, said 34 other people were injured in the accident on Saturday south of Shiraz, the province’s capital.

Abed said rescue operations are ongoing, and additional information and final figures will be released to the public after the operation is complete and detailed investigations have been carried out.

The cause of the incident is under investigation.

With nearly 17,000 casualties annually, Iran is among the countries most affected by road and street accidents. The high toll is attributed to lax application of safety measures, the widespread use of old vehicles and depleted emergency services.