The Swiss government said it is ready to confiscate UBS client information to prevent the bank from violating secrecy laws by handing documents over to the U.S. government.

The IRS is battling in a Miami court to force UBS to provide information on the accounts of 52,000 U.S.-based taxpayers. However, UBS contends that doing so would violate Swiss banking secrecy laws. Instead, the bank has chosen to close many of the clients’ accounts.

In a statement released by the Swiss Federal Department of Justice and Police, Switzerland on Tuesday confirmed that Swiss law prohibits disclosing the client information. “Switzerland makes it perfectly clear that Swiss law prohibits UBS from complying with a possible order by the court in Miami to hand over the client information,” said the department. “In addition, on the basis of the Federal Council’s decision of principle, UBS will by no means be in a position to comply with such an order. According to that decision, all the necessary measures should be taken to prevent UBS from handing over the information on the 52,000 account holders demanded in the U.S. civil proceeding.”

The department added that if circumstances require, it would issue an order explicitly prohibiting UBS from handing over client information.

In February, the bank signed a deferred prosecution agreement with the U.S. Justice Department, agreeing to pay $780 million and provide the names of 250 U.S. clients who had been accused of tax fraud (see UBS Agrees to Reveal Tax Shelter Clients). However, the IRS has continued to sue the bank to learn the identities and holdings of an additional 52,000 UBS clients by issuing “John Doe” summonses. The U.S. and Swiss government have made progress on a treaty to share more taxpayer information (see U.S., Swiss to Share More Taxpayer Information). But the legal battle over the 52,000 UBS clients threatens to derail the treaty.