The United States will continue efforts to enforce a summons demanding the names of the U.S. owners of roughly 52,000 accounts with UBS AG, the Justice Department said in a statement Tuesday.

Charles Miller, a Justice Department spokesman, said the United States will file a brief in federal court by the end of this month asking the Swiss banking company to turn over the names.

The Justice Department denied that it was settling its civil complaint against UBS. It issued the statement after The New York Times reported Monday that the department was weighing dropping its case to defuse diplomatic tensions with Switzerland.

"While the Department is always willing to consider settlement in any case, the suggestion that the Department is planning to drop this suit is simply untrue," Miller said.

"The Department is continuing with the case against UBS and will file its brief asking the court to enforce the summons on June 30," he said.

In February the United States settled a criminal case against UBS, which agreed to pay $780 million and turn over some account holders' names to avoid prosecution.

Now, several close deadlines are prompting more account holders to come forward and settle their debts with the Internal Revenue Service, lawyers close to the case say.

The terms of an IRS settlement offer expire Sept. 23.

In addition, there is a June 30 deadline for account holders to file a Foreign Bank Account Report disclosing their offshore holdings with the IRS. UBS account holders that want to avoid additional penalties are seeking to disclose before that deadline.

Finally, there will be a July 13 hearing of the U.S. District Court in Miami in the Justice Department complaint against UBS.

However, reports of a settlement could have a damping effect on account holders' willingness to come forward, said Bryan C. Skarlatos, an attorney with the firm of Kostelanetz & Fink, who is representing some UBS account holders in the case.

"If people feel there is a settlement in the offing, they are more likely to wait and see what happens and delay coming forward regardless of the June 30 deadline, even though they have a legal obligation to come forward," Skarlatos said.

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