Iraqi Prime Minister Haider al-Abadi sacked the head of the Baghdad security command and other top officials after a bombing in the capital killed 292 people, his office said on Friday.
Abadi issued "an order to relieve the Baghdad Operations commander of his position," as well as removing officials responsible for intelligence and security in the capital, a statement said.
The head of the Baghdad Operations Command was Lieutenant General Abdulamir al-Shimmari.
An official in Abadi's office said the others removed were the head of interior ministry intelligence for Baghdad and the official responsible for the capital in the national security adviser's office.
Iraq's interior minister tendered his resignation after the bombing, one of the deadliest to ever hit Iraq, but the Friday statement was the first announcing that officials were fired following the attack.
A suicide bomber detonated an explosives-laden minibus in a Baghdad shopping district early on Sunday as it teemed with people ahead of the holiday marking the end of the holy Muslim fasting month of Ramadan.
The blast, which was claimed by the Islamic State jihadist group, killed 292 people.
Authorities are still working to identify those killed in the attack, but Health Minister Adila Hamoud said on Thursday that the identities of 177 bodies had yet to be determined.
The initial blast killed a limited number of people, but raging flames spread and trapped people inside shopping centres at the site that lacked emergency exits, police Major General Talib Khalil Rahi said.
Interior Minister Mohammed Ghabban submitted his resignation following the bombing, and authorities also anno unced new security measures, the execution of five convicts and the arrest of 40 jihadists in an apparent bid to limit the fallout from the attack.
Ghabban criticised the security system as fundamentally flawed, saying he could no longer accept responsibility for the consequences and calling for a series of changes that would ultimately increase the ministry's power.
An official in Abadi's office told AFP on Wednesday that the premier had accepted the minister's resignation, though there has been no official statement from him on the matter.
IS overran large areas north and west of Baghdad in 2014, but Iraqi forces have since regained significant territory from the jihadists.
In response to the battlefield setbacks, the Sunni extremist group has hit back against civilians, and experts have warned there may be more bombings as the jihadists continue to lose ground.