Iraqi officials say the death toll from a car bombing in Baghdad has climbed to at least 45 people.
The blast occurred in a commercial area in a predominantly Shiite neighbourhood of Iraq's capital.
Two police officers say the explosives-laden car that went off at a crowded outdoor market in Baghdad's eastern district of Sadr City on Wednesday morning also wounded up to 65 people, several seriously.
There are fears the death toll will rise further.
Shortly after the explosion - one of the deadliest recently in Baghdad - the Sunni extremist Islamic State (IS) group, which sees Shiite Muslims as apostates, claimed responsibility for the attack in an online statement. It said the assault was carried out by a suicide bomber, but Iraqi officials denied that.
Several cars and nearby buildings were also heavily damaged, police officials said.
Karim Salih, a 45-year old grocer, said the bomb was a pick-up truck loaded with fruits and vegetables that was parked by a man who quickly disappeared among the crowds of people.
"It was such a thunderous explosion that jolted the ground," Salih said.
"The force of the explosion threw me for metres and I lost consciousness for a few minutes," the merchant added. He suffered no injuries, but two of his workers were wounded.
Four medical officials confirmed the casualty figures.
In its online statement, IS said it had carried out a suicide attack that targeted a gathering of Shiite militiamen.
IS also controls a significant area in northern and western Iraq, including its second-largest city of Mosul. Commercial and public places in Shiite-dominated areas are among the most frequent targets for the Sunni militants seeking to undermine Iraqi government efforts to maintain security inside the capital.
While IS has suffered a number of territorial defeats in the past year, the militants are still capable of launching significant attacks across the country, and have recently stepped up assaults inside Baghdad, something officials say is an attempt to distract from their recent defeats on the battlefield.
In February, the group carried out devastating back-to-back market bombings in Sadr City, the stronghold of followers of an influential Shiite cleric. That attack claimed the lives of at least 73 people.
According to the United Nations, at least 741 Iraqis were killed in April due to ongoing violence. The UN mission to Iraq put the number of civilians killed at 410, while the rest it said were members of the security forces. A total of 1,374 Iraqis were wounded that month, UNAMI (United Nations Assistance Mission for Iraq) said.
In March, at least 1,119 people were killed and 1,561 wounded in the ongoing violence.