A wave of car bombings targeting Shia pilgrims has killed at least 65 people and wounded another 200 in several cities across Iraq, in one of the deadliest attacks since US troops withdrew from the country.
The bloodshed was a stark reminder of the political tensions threatening to provoke a new wave of sectarian violence that once pushed Iraq to the brink of civil war.
Nobody immediately claimed responsibility for the attacks, but they bore the hallmarks of Sunni insurgents who frequently target Shias in Iraq.
The blasts were the third attack this week targeting the annual pilgrimage that sees hundreds of thousands of Shias converge on Baghdad to commemorate the eighth century death of revered Imam Moussa al-Kadhim, who is interred in a shrine in the northern region of Kazimiyah.
Most of the 16 separate explosions that rocked the country targeted the pilgrims, but two hit offices of political parties linked to Iraq's Kurdish minority.
Authorities had tightened security ahead of the pilgrimage, including a blockade of the mainly Sunni area of Azamiyah, which is near the twin-domed Shia shrine.
The level of violence has dropped dramatically in Iraq since peaking in 2006-2007 as the country faced a Sunni-led insurgency and retaliatory sectarian fighting that broke out after the US-led invasion that ousted Saddam Hussein.
But political divisions have only deepened, paralysing the country since the Americans withdrew all combat troops in mid-December.
Shia Prime Minister Nouri al-Maliki has been accused of trying to monopolise power, and tensions spiked after Vice President Tariq al-Hashemi - the highest-ranking Sunni in Iraq's leadership - was charged with running death squads.
The government began his trial in absentia since al-Hashemi was out of the country, drawing allegations the charges were part of a vendetta by the Shia-led government. The political stagnation has set back hopes for stability in Iraq and stalled efforts to rebuild the country after eight years of US occupation.