The deadliest attacks targeted the poor Shiite district of Sadr City in eastern Baghdad, as people went about their late afternoon shopping.
Two cars exploded in the Al-Ula market within minutes of each other, followed by one in Kayara market. There two other in Mreidi market and one in Dagher market. A seventh car bomb was defused.
The bombings in Sadr City claimed the lives of 46 people and wounded 204 others and authorities immediately appealed for blood donors.
Police were ordered to increase their presence around Sunni mosques for fear of retaliation.
"There are continuous efforts by the terrorists to promote sectarian conflict so there is a need to deal with the threat on an urgent basis and form a government of national unity," US ambassador to Iraq Zalmay Khalilzad said earlier.
Parliament opening brought forward
Sectarian violence across Iraq escalated following the bombing of a revered Shiite mosque in Samarra, north of Baghdad, on February 22.
The latest attacks targeted a bastion of two million Shiites controlled by radical cleric Moqtada Sadr's militia, which is suspected of carrying out reprisal attacks against Sunnis.
The onslaught came hours after politicians suddenly brought the opening date of Iraq’s new parliament forward from Sunday to Thursday.
They had been postponing the opening because of a dispute over who should be prime minister in the next broad-based coalition government which was elected three months ago.
The opening of parliament was advanced "to indicate that things need to move on a faster pace", and so that its timing did not clash with a Shiite holiday, honoring Imam Hussein, said US ambassador Zalmay Khalilzad.
The Shiite-led government fears there could be yet more attacks against Shiite pilgrims as they stream to the holy cities of Karbala and Najaf, in the south of the country, in the coming week for their religious festival Arbaeen.
Saddam trial
Meanwhile, the chief prosecutor at the trial of Saddam Hussein urged that the ex-president be swiftly hanged if found guilty.
Jaafar Mussawi said on television that execution need not await the outcome of future trials if the ousted dictator were found guilty in the first case brought against him and were sentenced to death.
Saddam and seven co-defendants are currently on trial for the killing of 148 Shiites from the village of Dujail following an assassination bid against Saddam in 1982.
"If the court passes a death sentence on any of the defendants in the
Dujail case, the law is clear, the sentence must be carried out within 30 days following the appeal," Mr Mussawi said.
On Sunday, three low-level members of Iraq's former ruling party, on trial with Saddam and four other co-accused, denied involvement in the Dujail killings.
It was the first time since the trial opened in October that they had been invited to testify as to their role in the deaths.
The 15th hearing in the trial, which opened in October, marked the first time the accused were invited to testify as to their role.