Switzerland's lower House of Parliament on Tuesday backed a crucial Swiss-U.S. pact over the disclosure of account details of suspected tax dodgers, raising prospects for a final approval.

However, it said it wants the pact to be put to a popular referendum, in contrast to the upper House of Parliament, which last week passed the bill but remained opposed to a public vote on the issue.

Both houses have until June 18 to resolve their differences.

The original agreement between the Swiss cabinet and U.S. authorities was worked out in August 2009. It would force UBS AG to disclose 4,450 UBS account holders' names to U.S. authorities until August 2010, a consequence of the bank's alleged setting up of tax-evasion schemes.

Subjecting the contract to a referendum would likely mean a failure by Switzerland to meet the August deadline because of the months it takes to hold a signature drive to launch a referendum in Switzerland.

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