HARRISBURG, Pa. - The largest provider of student loans in the U.S. is accused of "predatory" lending practices that harmed borrowers.

In a new federal lawsuit, Pennsylvania's attorney general said the nation's largest student loan company engaged in abusive practices that have cost borrowers billions of dollars. The complaint filed Thursday in federal court in Harrisburg, Pennsylvania, said Navient Corp. (NAVI) and Navient Solutions LLC sold "risky and expensive" subprime loans and damaged borrowers and co-signers by failing to perform core loan servicing duties.

"Navient's deceptive practices and predatory conduct harmed student borrowers and put their own profits ahead of the interests of millions of families across our country who are struggling to repay student loans," Attorney General Josh Shapiro said in a statement announcing the suit. "The more businesses like Navient put their bottom line ahead of the interests of their customers and consumers, the more vigilant we will be to protect Pennsylvanians and hold businesses like Navient accountable for their misconduct."

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The lawsuit also said the companies funneled people into a program that added massive interest costs when they should have been directing them into repayment plans indexed to income.

As of 2016, college graduates in the state owed an average of $35,759 in student loans, second only to New Hampshire.

Shapiro's office is asking for Navient to offer full restitution to any borrower affected by the company's practices, to disgorge "unlawfully gained" profits and to end collections on what he termed the "illegal loans" specified in the suit.

Navient issued a statement saying the allegations are completely unfounded and that it complies with federal rules for student loans.

The Consumer Financial Protection Bureau, Illinois and Washington state also sued Navient over its loan practices earlier this year.