KARBALA, Iraq: Huge crowds of black-clad Shiite Muslim pilgrims thronged the Iraqi shrine city of Karbala on Wednesday, weeping and beating their chests in mourning for the seventh-century killing of the prophet´s grandson.

Shiites around the world mark Ashura, but attacks on those commemorating bloodshed 1,300 years ago often result in more mourning and loss, including in Afghanistan, where at least 28 people were killed in attacks on Shiites in less than 24 hours.

Fourteen were gunned down at a mosque in Kabul on Tuesday night, while a bomb hit a mosque in northern Afghanistan on Wednesday, killing 14 more, officials said.

Shiites in Iraq too have come under frequent attack, mostly by Sunni extremists of the Islamic State group who regard them as heretics.

Some 30,000 security personnel were on the streets in and around Karbala to protect pilgrims, although attacks inside the city are rare.

The annual Ashura commemorations mark the killing of Imam Hussein by the forces of the Caliph Yazid in 680 AD — a formative event in Shiite Islam.

The pilgrimage draws huge numbers of faithful, with Haider al-Salami, spokesman for the Imam Hussein shrine, saying two million people took part in a ritual run from outside the city to the mausoleum.

Earlier in the day, black-clad pilgrims massed at the shrine to listen to a recitation of the story of Hussein´s death, with some beating their chests or heads and weeping in mourning.

Then came the ritual run, followed by the burning of a tent representing Yazid´s forces destroying Imam Hussein´s camp — the last of the rituals.

“We will continue to commemorate the imam despite terrorist threats,” said Saad Jassem, a 35-year-old from nearby Najaf, another Shiite shrine city.

Fellow pilgrim, Karim Hussein, 40, from the southern port city of Basra, said taking part carried a message for corrupt Iraqi politicians, who have come under mounting fire over the past two years but have done little to reform.