WASHINGTON (Reuters) - Democrats in the House of Representatives were set to release legislation on Wednesday extending lower tax rates for incomes up to $200,000 only, letting Bush-era rates for the wealthiest Americans rise.

The bill, obtained by Reuters, extends certain lower tax rates that will expire at the end of the year, enacted under former President George W. Bush.

The House is expected to vote on the proposal on Thursday but such a measure would face a tough road in the Senate.