Iraqi Prime Minister Nouri Maliki has called for the immediate arrest of those behind a mass kidnapping from a government building in Baghdad.
Maliki demanded the release of the remaining captives
The authorities say about 40 people taken from the higher education ministry building by gunmen in interior ministry uniforms have been released.
Police say they are attempting to free more, but there are conflicting reports of how many are still being held.
Later on Wednesday, a car bomb exploded in Baghdad, killing at least 11 people.
The blast occurred in central Baghdad, near a petrol station close to the interior ministry.
'Worse than extremists'
The Iraqi presidential security adviser, Wafiq al-Samaari, said higher education ministry hostages had been freed in intensive police operations across the Iraqi capital.
Five Iraqi police commanders are being investigated, including the police chief of Karrada district where the abductions occurred.
Mr Maliki said the militants behind the daylight raid were "worse than extremists", and added: "What happened was not terrorism, rather it was due to dispute and conflict between militias from one side or another."
He went on to demand the release the remaining captives.
He was speaking at Baghdad university during a visit to calm professors and students.
The militants behind the mass kidnap were wearing uniforms that had been specially designed for the ministry of interior.
Many here feel this is yet another example of collusion within the Iraqi police force - something the prime minister is trying desperately to stamp out, says the BBC's Andy Gallacher in Baghdad.
The armed gang responsible locked the women present in a room and drove off with the men in a fleet of vehicles.
Initial estimates had suggested that more than 100 people had been seized, but that was later revised down throughout the day.
Baghdad has been plagued by sectarian violence between Sunni and Shia communities, with so-called "death squads" regularly said to have strong links to elements of the Shia-dominated government.