The insurgent, who was not identified by name, "admitted to carrying out more than 30 assassinations and bombing operations," including setting off a car bomb in the Hurriyah area of the capital earlier this month, Baghdad Operations Command spokesman Colonel Dhia al-Wakil said in a statement.
A car bomb in Hurriyah killed three people and wounded 14 others on September 9, one of more than 30 attacks across Iraq that day.
Mr Wakil said that further details will be released after the investigation is completed.
And a bomb in Mahmudiyah, south of the capital, killed one person and wounded at least one, the same sources said.
With the latest violence, at least 200 people have been killed and 693 wounded in attacks so far this month, according to a tally based on security and medical sources.
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