At least 42 people have been killed after a motorcycle rigged with explosives was detonated in Baghdad's Sadr City and armed men targeted mostly Shia neighbourhoods around the country.
The motorcycle was parked in a second-hand market in the Shia Muslim neighbourhood that sells used bikes and was
filled with people, mostly young men, when it exploded late on Thursday afternoon, killing 31 and wounding 51 others, Iraqi medical and police sources said.
Storefront windows were shattered and shoes and motorcycle parts were strewn around the market, according to a Reuters' correspondent at the scene.
It was not clear who was behind the bombing but violence against Shia Muslims is often blamed on the Sunni Islamic State of Iraq and the Levant (ISIL), a group that al-Qaeda central leadership has disowned.
In other violence Thursday, four people died from bombs on two different mini-buses in Shia sections of Baghdad.
An attacker smashed his explosives-packed vehicle into a checkpoint, killing three soldiers and wounding six others in Mushaada, a Sunni district, in northern Baghdad, police said.
In Salahuddin province, a pro-government Sunni-manned checkpoint in the town of Shirqat was hit by a bomb that killed two fighters and wounded four others, police said.
Also to the north in Tuz Khurmatu, a bomb in an outdoor marketplace frequented by Shia Turkmen killed two people and wounded 11 others.
Baghdad has been hit by wave after wave of bombings since April as the precarious peace enjoyed since the end of Iraq's sectarian war in 2008 has unravelled.
Explosives and suicide bombs have been favoured by Sunni fighters as they seek to target Shia areas and intimidate their own religious community.
The latest bloodshed comes as the prime minister, Nouri al-Maliki, wages a war against Sunni Arab fighters in western Anbar province neighbouring Syria, and has become a base for ISIL.
Despite the offensive, the pace of attacks around the country goes on undiminished.