An Iraqi army colonel is under arrest today after four bomb attacks killed 183 people.
Suspected Sunni insurgents penetrated the Baghdad security net yesterday, targeting Shia areas.
Last night, Iraqi Prime minister Nouri Maliki ordered the arrest of the colonel, in charge of security in the regions around the Sadriyah market where at least 127 died and 148 were wounded.
Nationwide, the number of people killed or found dead was 233, which was second only to a total of 281 killed or found dead on November 23rd, 2006, according to Associated Press records, which began in May 2005.
Among the dead were several construction workers who died in an explosion at about 4.05pm, according to witnesses. They had been rebuilding the mostly Shia marketplace after a bombing destroyed many shops and killed 137 people there in February.
About an hour earlier, a suicide car bomber crashed into an Iraqi police checkpoint at an entrance to Sadr City, the capital's biggest Shia Muslim neighbourhood and a stronghold for the militia led by radical anti-US cleric Muqtada al-Sadr.