Story highlights Amnesty accuses Australian government of "mass cover-up" of abuse on Nauru

2,000 leaked case reports reveal catalog of abuse, according to the Guardian

(CNN) Amnesty International has accused the Australian government of a "mass cover-up" after more than 2,000 case reports were leaked detailing abuse on the Pacific island of Nauru.

Published by the Guardian , the documents were reportedly written by guards, caseworkers and teachers working at the Australian immigration center on the tiny island between May 2013 and October 2015.

They detail a devastating catalog of self-harm attempts, violent altercations, hunger strikes and incidents of sexual assault and child abuse, according to the newspaper.

The Australian Department of Immigration and Border Protection sent CNN a statement saying that many of the reported incidents were unconfirmed allegations, and the files themselves are evidence of the "robustness" of reporting procedures. It also said that "many of the incidents are historical in nature."

It said it's "seeking urgent advice from its service providers today to confirm all of these matters have been previously and appropriately reported to it, consistent with the policies and procedures covering such matters."