Shia Muslims slash and whip themselves to mourn the death of Prophet Muhammad's grandson

The rituals mark the holy Day of Ashura, when Shi'ite Muslims remember the death of Imam Hussein

Iraq Shi'ite Muslim men bleed as they slice their foreheads with swords and beat themselves to commemorate Ashura in Sadr City, Baghdad. (Reuters)

Shia Muslims worldwide cut themselves with swords and knives, covered their bodies with mud and lit bonfires in the streets to mourn the death of the Prophet Muhammad's grandson today.

The rituals mark the holy Day of Ashura, which is the tenth day of the "mourning month" of Muharram, when Shi'ite Muslims remember the death of Imam Hussein (Husayn Ibn Ali) at the Battle of Karbala in 680 AD.

Imam Hussein's martyrdom is widely interpreted by Shia as a symbol of the struggle against injustice, tyranny and oppression.

It is observed through mourning rituals and self-flagellation to varying degree in countries, including Pakistan, Iraq and Greece.

While cutting the body with knives or chains was banned in Iran and Lebanon, it is still practiced in Bangladesh and India.

Some flagellation rituals use a sword.

Thousands of Muslims listened to accounts of Imam Hussein's death under the golden dome of his mausoleum in Karbala, Iraq.

In Iran, hundreds of people covered themselves in wet mud and walked around bonfires to dry the mud to their skin and clothes.

The holy day was marred by a suspected suicide bomb in Pakistan, which killed at least 24, the BBC reported. At least five children were among the dead.