At least 19 people have been killed and 24 others injured in a bus crash in northern Iran, local media say.

The vehicle plunged into a ravine in the Veresk area of Mazandaran province, about 130km (80 miles) east of Tehran, according to the Isna news agency.

Officials were cited as saying that the crash happened when the bus’s brakes failed.

A pregnant woman and four children under the age of six were reportedly among the victims.