The U.S. Immigration and Customs Enforcement agency released nearly 600 illegal immigrants convicted of sex crimes, many because their home countries refused to take them back, according to newly obtained documents.

ICE said that a total of 564 illegal sex criminals were let go for legal reasons in the latest accounting period, fiscal 2015.

Of those, ICE was forced to release 151 because their native nations would not accept them. Under a 2001 Supreme Court case, the government can't indefinitely jail illegals ordered deported if their home countries won't take them back.

The documents, obtained by the Immigration Reform Law Institute under the Freedom of Information Act, do not give names or locations of the illegals, but do provide a general classification of the sex crimes. They are:

95 convicted of "commercialized sexual offense."

275 convicted of "other sexual offenses."

194 convicted of "sexual assault."

Of the total, 218 were granted bond by an immigration judge and 12 released due to "prosecutorial discretion," including consideration under DACA, or deferred action for childhood arrivals.

The numbers and crimes are a shock to groups pushing for tougher immigration policies.

"The anti-borders left routinely inject sanctimony into the immigration issue claiming that anyone with opposing arguments is morally inferior," said Dale Wilcox, executive director of the Immigration Reform Law Institute.

"But when statistics like this come out, statistics which show the horrific consequences of having an unregulated immigration system, they merely step over them like they don't exist," he added.

His group has a solid record of obtaining insider documents that show flaws in the immigration system.

The documents note that the number of sex criminals released could be higher because other law enforcement agencies also hold the illegals.

Paul Bedard, the Washington Examiner's "Washington Secrets" columnist, can be contacted at pbedard@washingtonexaminer.com