Amid chilly temperatures and heavy security, thousands of black-clad pilgrims from across Iraq marched on Thursday in the annual procession marking the death of a revered Shia imam.

Pilgrims traditionally travel on foot to the shrine and burial site of Imam Moussa al-Kadhim, the seventh of 12 Shia imams who died in a Baghdad prison in the eighth century.

The procession leads to the site in the northern Baghdad suburb of Kadimiyah.

Participants wear black, with some carrying out self-flagellation to publicly express their mourning.

Tents were pitched along the miles of road that the pilgrims were walking along on Thursday, handing out food and water free of charge.

Thousands of Iraqi security forces were deployed across the city to ensure the safety of the pilgrims, while some roads and bridges were closed to vehicles to allow pedestrian traffic only.

Sadiq Jaffar, 27, of Baghdad, told the Associated Press he was taking part in the pilgrimage “because it is important to my identity, despite all the problems that the country is facing such as the increase in the price of food and the rampant corruption”.

This year’s pilgrimage takes place just ahead of the 20-year anniversary next month of the US invasion of Iraq that led to the downfall of long-time dictator Saddam Hussein. Hussein had banned such pilgrimages from taking place.

During years of civil war that followed, insurgents repeatedly targeted Shia pilgrims during their religious ceremonies.

Iraq emerged from a year-long political stalemate with the formation of a government in October, but hopes for stabilisation of the political and economic situation were short-lived.

Measures taken by the United States in recent months to stamp out money laundering and the channelling of dollars to Iran and Syria from Iraq have severely restricted Iraq’s access to hard currency, leading to devaluation of the currency and inflation of prices.