The Union of Iranian Truckers and Heavy Vehicle Drivers said in a statement on Sunday that police used pepper spray on protesting drivers and arrested several of them.
Launched on May 22 in the southern port city of Bandar Abbas, the coordinated protest has since spread widely across the country, with truckers pledging to hold out for a full week or longer if their demands remain unmet.
Drivers are demanding better working conditions, higher freight rates, and relief from high insurance costs and fuel restrictions.
On Sunday, drivers in the southeastern cities of Jiroft and Sirjan, the western cities of Shabab in Ilam province and Asadabad in Hamadan province, and several locations in Tehran province, including Pakdasht, joined the strike.
Videos show parked freight trucks, drivers refusing cargo, and protest actions such as horn-blaring. The strike has disrupted traffic on key highways and industrial zones.