The latest violence is part of a protracted surge in nationwide bloodshed that has left more than 2,400 people dead since the start of the year and sparked fears Iraq is slipping back into the all-out sectarian fighting that plagued it in 2006 and 2007.
The unrest has been driven principally by anger in the Sunni Arab community over alleged mistreatment at the hands of the Shiite-led government and security forces, as well as spillover from the civil war in neighbouring Syria.
Maan said the fighters were part of the jihadist Islamic State of Iraq and the Levant, and were planning to attack an army base they had attempted to hit last week.
Despite the tactical success, the killings illustrate the growing ambition of ISIL militants seeking to fight their way into Baghdad, with analysts and officials worrying they are seeking to derail the April 30 elections.
More From This Section
Elsewhere in Iraq today, attacks north of the capital killed 19 people, security and medical officials said.
A car bomb set off by a suicide attacker at a checkpoint in the city of Tuz Khurmatu killed four policemen, while three others were killed by a similar attack in Mishahda, just north of Baghdad.
Shootings and bombings in and around Baquba, Tikrit, Baiji and Mosul left six others dead.
Diplomats and analysts have urged the government to reach out to the Sunni community to undermine support for militancy.