killed at least 39 people in an attack on a busy 
square in Baghdad's sprawling Sadr City district.
Another 20 civilians were killed elsewhere througout the Iraqi capital on Monday. 
A bomber driving a pickup truck struck an outdoor fruit and vegetable market, hitting daily labourers and a police checkpoint.
The Islamic State of Iraq and the Levant (ISIL, also known as ISIS) took responsibility for the blast via its Amaq website, claiming the "martyrdom operation"
Prime Minister Haidar al-Abadi said the bomber pretended to be seeking to hire day labourers. Once the workers gathered around, he detonated the vehicle.
Shia militiamen loyal to Muqtada al-Sadr, the firebrand cleric for whose family the neighbourhood is named, were seen evacuating bodies in their trucks before ambulances arrived.
Dead bodies were scattered across the bloody pavement alongside fruit, vegetables and labourers' shovels and axes. A minibus filled with dead passengers was on fire.
Asaad Hashim, an owner of a mobile phone store nearby, described how the labourers pushed and shoved around the bomber's vehicle, trying to get work for the day.
"Then a big boom came, sending them up into the air," said the 28-year old, who suffered shrapnel wounds to his right hand. He blamed "the most ineffective security forces in the world" for failing to prevent the attack.
An angry crowd cursed the government, even after a representative of al-Sadr tried to calm them. Late last month, Iraqi authorities started removing some of the security checkpoints in Baghdad in a bid to ease traffic for the capital's six million residents.
"We have no idea who will kill at any moment and who's supposed to protect us," said Ali Abbas, a 40-year-old father of four who was hurled over his vegetable stand by the blast. "If the securities forces can't protect us, then allow us to do the job."
Several smaller bombings elsewhere in the city on Monday killed another 20 civilians and wounded at least 70, according to medics and police officials.
Baghdad has been the focus of renewed violence over the past few weeks. ISIL also claimed an attack in central Baghdad that killed at least 27 people on Saturday.
Meanwhile, gunmen wearing suicide vests attacked two police stations in the central Iraqi city of Samarra on Monday, killing at least seven policemen, security sources said.
A military operations commander in the city told Al Jazeera both attackers were killed and the situation was under control.
US-backed Iraqi forces are currently fighting to push ISIL fighters from the northern city of Mosul, the armed group's last major stronghold in the country, but are facing fierce resistance.
Since the offensive began on October 17, Iraqi forces have retaken a quarter of the city in the biggest ground operation in Iraq since the 2003 US-led invasion that toppled Saddam Hussein.
As clashes continued in and around Mosul, ISIL - which took the city in 2014 - also targeted on Monday military positions away from the main battlefield.
Fighters attacked an army barracks near Baiji, 180km north of Baghdad, killing four soldiers and wounding 12 people, including Sunni tribal fighters, army and police sources said.
They seized weapons there and launched mortars at nearby Shirqat, forcing security forces to impose a curfew and close schools and offices in the town, according to local officials and security sources.
Shirqat mayor Ali Dodah said ISIL seized three checkpoints on the main road linking Baiji to Shirqat following the attacks. Shelling in Shirqat had killed at least two children, he told Reuters news agency by phone.
In a separate incident, gunmen broke into a village near Udhaim, 90km north of Baghdad, where they killed nine Sunni tribal fighters with shots to the head, police and medical sources said.
At least three pro-government Shia militia were also killed and seven wounded when fighters attacked their position near Udhaim with mortar rounds and machine guns, police sources said.