Most of the hostages seized in a raid by gunmen on a Baghdad higher education facility have been released, Iraqi officials have said.
Iraq's police apparently found the hostages across Baghdad
A government spokesman told the BBC that the hostages were freed in a number of police raids across the city.
Five top officers were later held - including the police chief of Karrada district where the abductions occurred.
It had earlier been reported all of the hostages had been released. Police say they are trying to free more people.
Gunmen dressed in uniforms similar to those worn by Iraqi police abducted dozens of people.
About 20 of the abductees had been released earlier on Tuesday evening.
The rest of the hostages were said to have been freed shortly before midnight in Baghdad (2100 GMT), according to presidential security adviser Wafiq al-Sammarai.
Initial estimates had suggested that more than 100 people had been seized, but that was later revised down throughout the day.
Reports said that there were about 40 still in captivity when the police operation set them free.
Some of the men released earlier in the evening said they had not been taken far, and had certainly not left Baghdad.
They were seized by at least 20 gunmen who posed as interior ministry police to seal off the street and gain entry to the higher education ministry.
They wore uniforms recently issued to officers which were thought to be difficult to copy.
The attackers stormed the education ministry's research department, locked women in a room and took the men away.
The daylight abduction and the use of apparently genuine government uniforms prompted questions about official involvement in the operation.
The five senior police officers held later on Tuesday were questioned by the interior minister, reports said.
Militias 'in conflict'
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.
Many of those seized from the higher education institute were said to have been driven towards Shia areas of Baghdad.
The building appears to have been a soft target for kidnappers
Mr Maliki said the abductions were part of ongoing disputes among groups linked to various political factions.
"What is happening is not terrorism, but the result of disagreements and conflict between militias belonging to this side or that," the Associated Press reported him as saying.
The attack on the higher-education institute was the latest to target Iraq's academics, who are increasingly fleeing the country in the face of the violence.
In other developments:
- A blast at Baghdad's Shurja market killed 10 people and wounded 25, police said
- An overnight US raid killed six people in mainly-Shia east Baghdad, sparking angry anti-US protests
- Thirty died in a US raid on the Sunni stronghold of Ramadi, Iraqi officials said
- Police found 11 bodies with gunshot wounds in Mosul, while 10 kidnap victims were found shot dead in Baquba