The White House and Republican members of the House committee responsible for tax policy promised Wednesday to work on a 10 percent middle-class tax cut in the next Congress.

“We are not done yet,” the Trump administration and the House Ways and Means Committee Republicans said in an unusual joint statement. “We are committed to delivering an additional 10 percent tax cut to middle-class workers across the country. And we intend to take swift action on this legislation at the start of the 116th Congress.”

[Related: Trump's promise of a new tax cut appears to fade]

The joint statement follows previous middle-class tax cut promises from President Trump that took his own party by surprise. Details of the promised 10 percent tax cut for the middle class remain scarce, if they exist.

Trump previously promised to enact the cuts prior to the midterm elections, an impossibility without Congress in session.

Preliminary estimates for a 10 percent tax cut aimed at the middle class are that it would cut federal government revenue by about $2 trillion over 10 years.

Last year's tax law has not been as popular as Republicans hoped it would be. House Republicans advanced legislation to make those cuts permanent in September, but the bill has yet to be considered in the Senate.