From across Iraq and neighboring states, millions of Shia pilgrims are heading this week to the city of Karbala for a religious ceremony that authorities say extremists are targeting for attack.
Already hundreds of thousands of Shis faithful, many from adjacent Iran, have visited Karbala for rituals which culminate in Saturday's Arbain holy day -- the last of 40 days' mourning for the death in battle of Imam Hussein 13 centuries ago.
Roads and highways across Iraq have been filled with black-clad pilgrims heading on foot to Karbala, a journey which can take days, carrying banners bearing Imam Hussein's image, Reuters reported. Arbain, a defining ritual of Shia Islam, has frequently been marred by militant attacks. This year it unfolds for the first time since IS militants seized control of much of north and west Iraq.
"We have information that they will try to infiltrate crowds of pilgrims and kill civilians everywhere," Iraqi Prime Minister Haider al-Abadi said this week during a visit to Karbala, about 50 miles (80 km) south-west of Baghdad.
Abadi said security forces would thwart any attempt to disrupt Arbain, but they face a double challenge. Not only are many troops diverted to tackle IS militants elsewhere -- forcing authorities to rely more heavily on Shia militia to keep order -- but this year's flood of foreign visitors has been swollen by Iraq's decision to ease visa requirements for Arbain pilgrims.
