WILLIAMSPORT -- Former Penn State defensive coordinator Bob Shoop said he left the Nittany Lions because of "intolerable" working conditions and that the university breached his contract, according to a counter lawsuit filed Thursday in U.S. Middle District Court.

Penn State is suing Shoop for almost $900,000, claiming he resigned with two years left on his contract to take the same job at Tennessee in January 2016.

But Shoop said, according to court documents, he "was constructively discharged/terminated from, or forced or compelled to leave his employment with Penn State."

He's seeking damages in excess of $75,000, which is the threshold to get a case into federal court.

In his complaint, Shoop said he wants the university to adhere to the termination without cause clause of his contract.

Shoop claims, under the clause, Penn State owes him money and has yet to pay it.

Shoop said he experienced "a hostile, negative work environment," but did not go into further detail in the court documents.

He claims the "intolerable" conditions began shortly after he signed his contract in 2015.

Shoop said he was "under duress" when he signed the contract but did not provide further explanation in the documents.

Shoop's claim came three days after PennLive first reported that PSU was seeking $891,856 from its former defensive coordinator.

Shoop said, in the court documents, he has not paid any of the money to Penn State and that he has informed the university, through counsel, he is refusing to do so.

Shoop contends the clause in his contract that required liquidated damages if he left and did not become a head coach within a year was a "punishment or threat" designed to prevent him from leaving Penn State.

He's seeking dismissal of Penn State's suit and said the university did not suffer any damages by him going to Tennessee.

The resignation clause of Shoop's contract, according to court documents, states if he resigned before his contract expired on Feb. 15, 2018, he had to pay the university liquidated damages of 50 percent of his base pay.

Shoop did not respond to a phone call or text Thursday.

When asked for a response to Shoop's accusations, Penn State responded with the same statement it issued Tuesday:

"Under the terms of his employment contract with Penn State, Coach Shoop is obligated to make a liquidated damages payment to the university resulting from the termination by Coach Shoop of his employment prior to the end of the contract term. We are filing suit against him to recover this mutually agreed upon amount."

Editor's note: This story has been updated to provide additional information from Shoop's response to Penn State's suit as well as additional information from his countersuit.