The operation, details of which remain unclear, took place Thursday when rapid intervention units and intelligence forces sought to storm a house in the village of Al-Rashayed in the central Iraqi province.

In a brief initial statement, security forces said they had "pursued two individuals accused of terrorism" who "opened fire indiscriminately" once surrounded.

An investigation was opened "after the discovery of a number of dead bodies of citizens in a house", the statement added.

On Friday, Interior Minister Othman al-Ghanemi travelled to Al-Rashayed where he sacked the police chief and announced the formation of a commission to investigate "the unit that carried out the operation".

The official Iraqi News Agency gave a death toll of 20 civilians from the same family, and said that the owner of the property had opened fire and "refused to surrender".

A separate statement from the security forces said a "number of officers and individuals" had been called in for questioning in connection with the incident, without providing details on their identities.

Interior ministry official Saad Maan posted a video of the premises on Twitter, showing a house with a blackened facade and gutted doors and windows.

He denounced a "crime on all levels", without identifying those to blame, and said the investigation was ongoing to "understand all the circumstances of the incident".

On Thursday evening, security sources and media outlets had suggested a suspect linked with the Islamic State group or drug trafficking rings had been involved.