A car bomb has killed at least 25 people and wounded about 60 others in the Iraqi capital, Baghdad, police say.
There has been a series of bomb attacks on Baghdad markets
The bomb exploded at about 1000 local time (0600 GMT) in an outdoor market in the mainly Shia Amil district, in the south-west of the city.
Many of those killed and wounded were women and children, medical and military officials said.
In separate attacks in eastern part of the capital, 12 students were killed and at least 28 injured, police said.
The Amil attack happened as the market was packed with shoppers.
Television pictures showed a scene of destruction across a wide area, with buildings badly damaged and cars wrecked.
Residents dug frantically through the rubble - many with their bare hands - in a desperate search for survivors.
Fadhil Hussein, who sells spices at the market, said: "There were four women around my stall when we heard a loud explosion, which threw me many metres away from my stall."
"I found myself in a pickup truck with other people. Some of them were bleeding and yelling," he told the Associated Press news agency.
Mr Hussein was hit in his back and head with pieces of shrapnel.
In two separate attacks later on Tuesday, 12 students died in eastern Baghdad.
In the first attack, mortar rounds landed on a college affiliated with Baghdad University, killing four students and injuring 25 more.
Hours later, gunmen fired on a minibus full of students from Mustansiriyah University. Eight were killed and three injured.
In other attacks across Baghdad, two Iraqi policemen were killed and one injured when their car was ambushed by gunmen in the Khadra district.
And a roadside bomb blast hit a police patrol car in the east of Baghdad, killing one policeman and injuring three.
The US military in Iraq said it killed nine suspected insurgents and freed 12 Iraqi hostages in a raid on a house in western Baghdad.
Thousands of extra US and Iraqi troops have been deployed in Baghdad in recent months in an attempt to quell sectarian violence in the city.
US officials say the number of sectarian murders has decreased in the three months since the security operation began, but car bombings are still a regular event in Baghdad and other cities across Iraq.
US and Iraqi troops are still searching for three US soldiers missing since their patrol was ambushed on 12 May.
Four US soldiers and one Iraqi were killed in the attack, near Mahmudiya, south of Baghdad.