Thousands of extra security personnel have been brought into the Iraqi city of Karbala after reportedly over 22 million Shia Muslims have descended upon the town for a holy ritual. Arbaeen marks the end of a 40-day period of mourning for the prophet Mohammad's grandson, Iman Hussein. The event has been a target for attacks in the past.

Hussein Ali, who visited from Iraq's southern city of Basra, said: "Security measures are very good. Roads used by walking pilgrims are secured and safe and all kinds of services are available. First aid and emergency services are available too".

Arbaeen is seen as a defining ritual for Shia Islam, and symbolic of their rift with Sunni Muslims. Armed guards could be seen in the city.

"All the security forces of the government including the Hashid Shaabi, security forces of interior ministry and the army are mobilised for the event and all the other ministries are helping in providing transport means to facilitate the moving of pilgrims," said Rasheed Kadhim Salman , a Shia from Nassiriya province.

Thousands travelled on foot to the ritual, with some walking all the way from Baghdad. Many beat their heads and whipped themselves as part of the ritual, which ends on 3 December.