U.S. Bank has sued financially troubled developer Opus Corp., claiming the bank is owed more than $78 million -- and alleging that Opus can't pay its debts because it fraudulently transferred money into trusts connected to founder Gerald Rauenhorst.

In the suit filed July 13 in U.S. District Court in Minneapolis, U.S. Bank says it was the lead banker on the $150 million line of credit provided to the Minnetonka-based developer in 2007. Other lenders include Bank of America, J.P. Morgan Chase Bank and Wachovia Bank, now part of Wells Fargo.

"After a preliminary analysis of the suit, Opus believes there are inaccuracies in the claims asserted against the companies and there are significant defenses," Opus spokeswoman Winston Hewett said in a prepared statement Thursday. "Opus will continue negotiations with the banks while simultaneously defending against the claims. Opus remains hopeful that a compromised settlement can be reached with the banks to resolve these claims."

The suit says the loan went into default in February. Last month, U.S. Bank notified Opus that it was accelerating payments under terms of the agreement. As of July 13, Opus owed about $75.2 million in principal and about $3.6 million in letters of credit, the suit says.

In the suit, U.S. Bank says it also is suing the trusts because Opus transferred about $193.8 million in assets to them from 2003 to 2008. "At least some of the transfers either resulted in Opus Corp. becoming insolvent, or were made at a time when Opus Corp. was insolvent," the suit said. As a result of the transfers, the company was unable to pay its debts, the suit says.

The suit says Opus also violated terms of the credit agreement by lending $45 million to Opus South, its Atlanta-based regional operating company, and $10 million to Opus West, its Phoenix-based regional operating company.

Both regional companies have filed for Chapter 11 bankruptcy. Opus Corp. has said it plans to shut down Opus South when its reorganization is complete and operate Opus West in a greatly reduced capacity. Opus also is liquidating its Washington, D.C.-based operating company, Opus East, which filed Chapter 7 bankruptcy earlier this month.