Kidnappers who seized dozens of men from an Iraqi government building two days ago tortured and killed some of them, the minister for higher education said on Thursday, citing the testimony of freed hostages.
The comments from Abd Dhiab, who also said some 70 hostages were still missing, underlined rifts in the government of Prime Minister Nuri al-Maliki, who has insisted that all but a handful of around 40 hostages have been freed.
Tuesday's raid by gunmen in police uniform raised new fears that sectarian militias were out of control, despite US calls for Maliki to disband armed groups loyal to his Shia allies.
One hostage, from the Sunni minority, spoke of being taken with dozens of others in a well-organised operation to the Shia militia stronghold of Sadr City before being released late on Wednesday: "I can't believe I'm alive," he told Reuters.
Speaking of his "great sadness", Maliki told reporters on a visit to Turkey his government was planning measures to improve security: "We will not allow revenge attacks," he said.
The fact that at least a substantial number of hostages, including Sunnis, were released may indicate a degree of success on the part of the government in applying pressure on militias that notionally support some of its key figures.
Higher Education Minister Dhiab, a Sunni, told Reuters around 70 hostages had been released out of about 150 staff and visitors seized from one of his ministry's buildings. "There are a number of people who were killed, they are employees and guards," Dhiab said, without specifying how many.