The mother of journalist Kenji Goto, who was executed by the Islamic State group in January, has said her son died because of government inaction, contradicting officials' assertions the crisis was handled appropriately.

In a statement Friday, Junko Ishido said she was "overcome with anger" upon reading a report released the previous day by a government panel that evaluated the government's response to the hostage crisis, in which her son and another Japanese national were killed.

The report concluded that Tokyo's handling of the crisis had been appropriate. No decision it made can be considered "misguided enough to have undermined the possibility of the captives' safe returns," the 45-page assessment said.