The blasts took place about the time that Iraqi Prime Minister Nouri al-Maliki commemorated the bombing of the Golden Dome mosque in Samarra, saying the country had no future unless a U.S.-backed offensive against militants in Baghdad succeeded, Reuters reported.
The bombs struck within a minute of each other about 12:25 p.m. local time during a government-called 15-minute period of commemoration for the mosque bombing.
Smoke billowed above the marketplace near the east bank of the Tigris River and the Central Bank. Ambulances rushed the estimated 165 wounded to nearby al-Kindi hospital.
Debris was scattered in pools of blood, and shops and stalls were obliterated, according to the Associated Press.
The bombings came despite the stepped up security in the capital as U.S. and Iraqi forces launched an operation aimed at stemming the sectarian violence.
Al-Maliki called on government offices and citizens to chant, "God is great" in all mosques and to ring bells for the Samarra anniversary.
"The explosion of the holy shrine pushed the country into blind violence, in which tens of thousands of innocents were killed," said Grand Ayatollah Ali al-Sistani, Iraq's top Shiite cleric, in a statement issued before Monday's bombings.
"No one knows but Allah when this tragedy will be over."
He also called for restraint among those observing the anniversary. "We call on the believers to express their emotions but to be cautious and act disciplined, and not to do anything to hurt our brothers the Sunnis, as they are not responsible for this awful crime."
About 16,000 demonstrators marched toward two Shiite shrines in Karbala, 50 miles south of Baghdad. Police reported no violence there, according to the AP.