Mourners: in their hundreds of thousands crowded the streets of Karbala on Friday, many beating their backs with metal chains as the Ashura mourning began building towards a peak.

The shrine city south of Baghdad was heavily guarded as devotees from across the Muslim world flooded through a long series of security checkpoints to reach the main focus of their pilgrimage — two imposing shrines, one to Imam Hussein and the other to Imam Abbas.

Around two million people are expected to be in Karbala by Saturday, guarded by a 20,000-strong security force.

Tents and small wooden rooms covered in black fabric and adorned with lights and pictures of imams have sprung up across the city for pilgrims in need of food or seeking a rest from the intense bustle of the streets.

According to the governor of Karbala, Akil al-Khazali, some 20,000 security personnel are on duty in the city for the event, including 500 women officers to frisk female pilgrims, following a spate of suicide bombings by women in Iraq in recent weeks. Last August a pilgrimage in Karbala became a bloodbath when police and gunmen of the Mahdi Army militia of radical cleric Moqtada al-Sadr clashed at the two holy shrines.

There is also a police and army presence of about 20,000 in Najaf, another shrine city and a stopping point for pilgrims about 50 kilometres from Karbala, police said.—AFP