Three bomb attacks at markets in central Baghdad killed at least 64 people on Monday as Iraqis marked the first anniversary of a Shi'ite shrine bombing that pitched the country to the brink of civil war.
In the deadliest attack, twin car bombings exploded in quick succession in the Shorja wholesale market, killing at least 59 people and wounding 150, police said.
Interior Ministry sources said the blasts were caused by a car bomb and a roadside bomb.
Huge clouds of black smoke and flames belched from a multi-storey building that houses wholesale clothing merchants, turning a cloudless day into night in the debris-strewn street.
The blasts, which echoed across Baghdad, reduced market stalls to mangled wrecks.
People with wooden carts carried badly wounded survivors with bandaged legs, arms and heads.
"I saw three bodies shredded apart and people wounded being transported by ambulances," said witness Wathiq Ibrahim.
"Paramedics were picking up body pieces and human flesh from the pools of blood on the ground and placing them in small plastic bags," he said, adding that 20 cars were set on fire.
"The smoke turned the place dark."
One old woman cursed the government of Prime Minister Nuri al-Maliki, who has launched a US-backed security plan in Baghdad that is seen as a last-ditch effort to avert all-out civil war between majority Shi'ites and Sunni Arabs.
"They've killed all our sons. What have they left for us?" she shouted.
A separate roadside bomb attack at the Bab al-Sharji market, also in central Baghdad and home to Sunni Arab and Shi'ite traders, killed at least five people, police sources said.
The attacks occurred around the same time as Shi'ite government officials, including Maliki, held several minutes of silence to mark the first anniversary under the Islamic calendar of the bombing of the al-Askari shrine in Samarra.
Under the Gregorian calendar the bombing was on February 22. Earlier, Iraq's top Shi'ite cleric, Grand Ayatollah Ali al-Sistani urged followers not to seek revenge against Sunnis.
Sistani said the Samarra bombing, blamed on Sunni militants, had plunged Iraq into a cycle of "blind violence".
Tens of thousands of Iraqis have been killed in a wave of sectarian attacks triggered by the destruction of the al-Askari mosque, one of the holiest in Shi'ite Islam.
Hundreds of thousands have been displaced to flee sectarian cleansing.