At least 31 people have been killed in a stampede during commemorations for the Shia holy day of Ashura in the Iraqi city of Karbala, officials say.

A health ministry spokesman said another 100 people were injured and warned that the death toll could rise.

The stampede reportedly occurred when a pilgrim tripped while hundreds of thousands were performing a ritual.

Ashura commemorates the martyrdom in battle of the Imam Hussein, a grandson of the Prophet Muhammad, in 680AD.

Every year, millions of Shia Muslim pilgrims travel to Karbala for Ashura, which falls on the 10th of Muharram, the first month of the Islamic lunar calendar. It is marked with mourning rituals and passion plays re-enacting Hussein’s martyrdom.