Iran's official IRNA news agency is reporting that a train derailed in the country's southeast, near the Pakistan border, killing four passengers and injuring at least 35 others.
Wednesday's report says rescue workers transferred injured passengers to hospitals in Zahedan city, the provincial capital of Sistan and Baluchistan province.
The train was on a 1,500-kilometer (930-mile) journey from Zahedan to Tehran, the Iranian capital.
IRNA said the incident happened when a wagon derailed because of sand on the rails in the Shuru area, some 60 kilometers (37 miles) southwest of Zahedan. The area is known for sudden sandstorms.
Occasional derailments happen in Iran but rarely lead to injuries or deaths, though in 2016 dozens were killed and scores injured when two Iranian passenger trains collided in northern Semnan province east of the capital Tehran.