UPDATE 1-Americans hid assets at Liechtenstein bank-senator

(Adds Levin, Uehlinger, S&P comments, background)

By Kevin Drawbaugh

WASHINGTON, Feb 21 (Reuters) - A senior U.S. lawmaker said on Thursday he would launch an investigation into U.S. citizens who hid assets at Liechtenstein's LGT Bank to avoid paying taxes and urged Senate passage of a bill to crack down on offshore tax havens.

"It is my understanding that many U.S. citizens have also hidden assets at this bank," said Sen. Carl Levin, a Michigan Democrat and chairman of the Senate's Permanent Subcommittee on Investigations. "I intend to investigate."

Hans-Martin Uehlinger, an LGT spokesman contacted by phone in Liechtenstein, declined to comment immediately, saying he had not yet seen Levin's statement.

LGT's Web site says it is a wealth and asset management group run by the princely house of Liechtenstein for more than 70 years, with 1,600 employees and 29 locations worldwide.

Police investigating tax evasion linked to Liechtenstein raided homes and bank offices across Germany on Monday.

"Recent events involving a bank in Liechtenstein once again demonstrate the problems presented by secrecy jurisdictions and tax havens that enable individuals to hide assets and evade taxes," Levin said in a statement.

Levin urged the Senate to pass a bill he introduced last year which he said would "combat offshore secrecy and end the use of tax havens such as Liechtenstein by U.S. citizens who are dodging their tax obligations, and ripping off America and honest American taxpayers in the process."

Sandwiched between Austria and Switzerland, the tiny principality of Liechtenstein is home to three mid-sized private banks -- Swiss-listed LLB (LLB.S) and VP Bank (VPB.S) and unlisted LGT Bank -- and many private wealth managers.

Levin said LGT "has apparently harbored numerous secret accounts which hid the taxable assets of thousands of citizens from around the world."

Standard & Poor's Rating Services on Tuesday revised its outlook for LGT to "negative" from "stable." The U.S. credit rating agency said it took the action on LGT "because of risks to the bank's reputation from an investigation by German fiscal authorities." (Editing by Braden Reddall)