At least 26 Shiite Muslim pilgrims headed to Iraq were killed and 28 injured in a bus accident in southern Iran, the ISNA news agency reported on Wednesday.
The bus was carrying pilgrims to the shrine city of Karabla to commemorate the Arbaeen, when its brakes failed and it flipped over on Tuesday evening.
Some 2.5 million Iranians are expected in Karbala this month for Arbaeen, which marks the 40th day after the death in the seventh century of Imam Hussein, one of the pivotal figures of the Shiite faith.
An estimated 16,000 people were killed in road accidents in Iran in the year to March 2016.
Erratic driving is common on Iran’s roads, but there has been an improvement compared with a decade ago when an average of around 28,000 people a year were killed.