UPDATE 3-UBS says gave US onshore bank client data

(Adds comments by UBS, Swiss Finance Ministry)

By Lisa Jucca

ZURICH, Nov 11 (Reuters) - UBS, the world's biggest bank to the rich, said on Tuesday it had given details to the United States of U.S. onshore bank accounts as part of a tax probe that is testing Swiss bank secrecy and UBS's reputation.

No data has been transferred from offshore or undeclared bank accounts located in Switzerland that are key to the country's long-standing tradition of bank confidentiality, UBS and the Swiss Finance Ministry told Reuters.

The probe focuses on whether Swiss bank UBS (UBSN.VX: Quote, Profile, Research) illegally helped wealthy Americans to dodge taxes through its offering of offshore services from 2000 to 2007. The bank was singled out by U.S. President-elect Barack Obama as one of those which helped "tax cheats".

"U.S. authorities have requested data from UBS on U.S. onshore clients," a UBS spokesman said. "UBS must comply with that request for information located in the United States."

The spokesman said the request was made in the third quarter of this year. He would not say how many U.S. onshore or declared bank accounts were involved.

The Swiss are still assessing a request by U.S. authorities for information about offshore bank accounts held by U.S. clients of UBS in Switzerland.

Switzerland does not consider tax evasion a crime and the Swiss Finance Ministry is the only authority in the country that could authorise the transfer of Swiss-based client data to the United States.