Geneva - The United States authorities and the Swiss bank UBS have filed a request Sunday to have their court case on client data postponed to allow for further negotiations, Swiss media reported.

The motion to delay the proceedings until August - if no agreement was reached - was filed as the clock ticked down to the start of the trial at 1300 GMT Monday in Miami, Florida.

The US wants UBS to hand over data on about 52,000 US-tax-paying clients of the bank. The Swiss government has said it would seize the data, if the US court demanded its disclosure, to prevent any violations of the Alpine confederation's banking confidentiality laws.

UBS has said it found itself stuck between the laws of two sovereign states.

US and Swiss officials are trying to negotiate a solution to the quagmire, and the motion wants to allow them more time for their talks.

Reports in the Swiss media have suggested the Zurich-based UBS might hand over some names, probably of clients who were involved in some form of tax fraud, if it could get a guarantee that the case would then be closed.

A spokesman for UBS declined to immediately comment saying the bank would release a statement later Sunday.

In February, one day after UBS admitted wrongdoings, handed over information on a reported 250 clients and agreed to pay 780 million dollars in fines, the US launched the new demand for more data. The bank's employees are said to have helped wealthy clients evade paying their taxes.

Switzerland is in the process of renegotiating its double-taxation agreements with various governments, including the US, in order to get off the Organization for Economic Cooperation and Development's so called "grey-list" of countries without sufficient disclosure. (dpa)