NEW YORK -- Indigenous boarding schools that native American children attended have surpassed the number of previously reported institutions, CNN reported on Wednesday, citing a non-profit group.

Native American children have attended at least 523 Indigenous boarding schools since the 19th century, including hundreds run by the federal government to assimilate them into White society, said the report.

The National Native American Boarding School Healing Coalition released a new list of Indigenous boarding schools, including many that have closed and some that are still in operation today.

"Throughout the 19th and 20th centuries, Native American children were sent to schools where they were renamed, told not to use Indigenous languages and had their hair cut," said the report. "Many (schools) operated like military training camps where children were subject to abuse, neglect and corporal punishment."

The US Interior Department's initial investigation found that 19 boarding schools accounted for the deaths of more than 500 American Indian, Alaska Native, and Native Hawaiian children but noted the number of recorded deaths was expected to rise, it added.