The women have been recently moved to a detention centre in Mosul from a camp located 60km south of Mosul city, where Iraqi authorities are still holding almost 800 children of Isis militants.
The spouses and their children were moved Sunday from a camp run by worldwide aid agencies 60 kilometres (40 miles) south of Mosul, said the official, who asked to remain anonymous.
A senior Iraqi security official told AFP news agency on Monday that the 509 women and 813 children belonged to 13 different nationalities from Europe, Asia and the Americas.
Four months later, prosecutors said, they were involved in the execution of a captured Iraqi military officer.
The IS still controls the western areas of Anbar.
The Norwegian Refugee Council said they group were mostly from Turkey, Azerbaijan, Russia and Tajikistan.
"The NRC demands that the Government of Iraq disclose the exact location of these people and the reasons for their transfer", it said in a statement. "Humanitarian organisations and representatives from their home countries should be allowed to offer to them help".
One foreign ISIS bride from Germany may not be so lucky, though. He ended up with IS in 2014 and fought against Kurdish forces in northern Syria before entering in Germany in August 2015.
Iraqi prime minister Haider Al Abadi announced the launch of the operation and vowed that forces "will retake every last bit of Iraqi territory from the enemy".