An Iraqi security source said Wednesday's bloodiest strike occurred in the Shia district of Kadhimiyah, where the toll rose to 112 there alone, from an earlier count of 80.
A total of 150 people were killed in 11 car bombings.
The slaughter came as Iraqi leaders completed a draft constitution to be put to a referendum in mid-October.
According to US and Iraqi officials, nearly 200 people were wounded in the bombings which fighters loyal to al-Qaida's Iraq frontman said were in revenge for a US-Iraqi assault on Sunni fighters in the northern town of Tal Afar.
The violence did not end with the dawn bombings. On Wednesday night, at least two Iraqis were killed and more than 50 wounded when a market was hit by mortar fire in a town south of the capital, officials and medics said.
In the attack which occurred around 8.00pm (1600 GMT), 11 mortar rounds struck the market in al-Madaien, a town of mixed Sunni and Shia Arabs located 16km from Baghdad, a Defence Ministry source said.
"Al-Kindi hospital in central Baghdad has received two dead and 23 wounded, the one in al-Madaien 25 wounded while the others were sent to the hospital in Zaafraniyah," an Interior Ministry source said.
Early on Wednesday morning, in the day's first deadly explosion, in the Shia district of Kadhimiyah construction workers from southern Iraq gathered waiting to be hired for work when the bomber struck.
Labourers circled the bomber's car as he pulled up posing as a potential employer.
Up to 17 Shia civilians were
executed in Taji's main square
"There were dozens and dozens of people around the car when it blew up," said Satah Jihad, a 40-year-old shopkeeper.
"I'm packing and going straight home," said a visibly shaken Ali Kamel, who had only arrived in the capital from the central city of Kut three days earlier to look for work.
"I saw dozens of bodies on the ground and dozens of injured people screaming," he said.
Iraqi journalist Ziyad al-Samaraei told Aljazeera that US and Iraqi forces converged on Kadhimiyah to transfer the wounded to different hospitals and gather up bodies.
Another car bomb exploded on Wednesday in al-Adhamiya area near Antar square, targeting an Iraqi police patrol and injuring four policemen, he said.
US forces were also hit on Wednesday by car bombs in al-Qana neighbourhood and the new Baghdad area, al-Samaraei said.
And Iraqi army forces came under a car bomb attack near al-Adel neighbourhood, he added.
The carnage was repeated across Baghdad through the morning rush hour and into the early afternoon as a total of 11 bombs went off.
Eleven US soldiers were hurt in four of the attacks, according to US military spokesman Sergeant David Abrams.
US troops were the target of
seven of the 11 bomb attacks
Two Iraqi policemen were also shot dead in an attack on a police post before a nearby bombing, the Interior Ministry said.
Seven of the 11 bomb attacks appeared to have been directed against US forces and the remainder against Iraqi security forces and civilians, according to a US military spokesman.
One would-be bomber, who ploughed into a US tank but whose explosives failed to detonate, was later killed when an ordnance-disposal team attempted to defuse a 155mm shell he was transporting.
"The terrorist was trapped inside" the car and "in the process of attempting to render the explosive neutral, it went off", US spokesman Abrams said.
In other violence, 17 Shia civilians were rounded up before dawn in the town of Taji, just north of Baghdad, and executed in a main square.
"Armed men dressed as soldiers and driving aboard military vehicles arrived in Taji and arrested several members of the Bani Tamin tribe before assembling them on a public square and shooting them," an Interior Ministry official said.
In another incident, an Iraqi general, Haider Ibrahim Ali, and a bodyguard were shot dead in Baquba, 60km north of the capital, police said.
"Armed men dressed as soldiers and driving aboard military vehicles arrived in Taji and arrested several members of the Bani Tamin tribe before assembling them on a public square and shooting them"
Iraqi Interior Ministry official
Iraqi leaders announced that they had finally handed over the text of a draft constitution to the United Nations on Wednesday, ending months of tortuous negotiations.
The deputy speaker of parliament, Hussein Shahristani, said some minor changes had been made to the wording of the text presented to parliament on 28 August in a bid to assuage Sunni objections.
The changes concerned references in the charter to the national identity of Iraq, as well as articles connected with the management of water resources and the rights of the prime minister, who will have two rather than three deputies.
But a leading Sunni group, the National Council for Dialogue, rejected the concessions and called on the minority to reject the text in a referendum due next month.
The Sunnis could still torpedo the draft if enough of them vote against it.
The rules for the poll stipulate that the constitution fails if two-thirds of the voters reject it in any three provinces.
Hussein Shahristani: Minor
changes were made to wording
At least three of Iraq's provinces are predominantly Sunni Arab.
The announcement of the final draft came one day after Iraqi President Jalal Talabani met President George Bush in Washington.
The draft constitution is "an historic milestone", Bush said.
"Iraqi people can be proud of the draft constitution and when an election to ratify the constitution is held next month, they'll have a chance to vote their conscience at the polls."
In northern Iraq, where some 10,000 US and Iraqi troops have been engaged in a massive offensive to recapture the ethnically divided town of Tal Afar from Sunni fighters, commanders spoke of "horrible" abuses that they had uncovered.
"The enemy here did just the most horrible things you can imagine, in one case murdering a child, placing a booby trap within the child's body and waiting for the parent to come recover the body of their child and exploding it to kill the parents," Colonel HR McMaster said.
"There were dozens and dozens of people around the car when it blew up"
Shopkeeper Satah Jihad
He said there had also been beheadings.
Commanders said on Tuesday that they were in full control of the town after the fighters melted away.
In an internet statement, Abu Musab al-Zarqawi's al-Qaida Organisation in the Land of Two Rivers claimed responsibility for the bombings in Baghdad, saying they were in revenge for the assault on Tal Afar.
"The conquest of revenge for the Sunni people of Tal Afar has started," said the statement, the authenticity of which could not be verified.