The tax reform framework introduced by Republicans this week would cut taxes by $2.4 trillion over a decade and provide the biggest tax cuts to high-income earners, according to the first outside analysis of the plan.

While most people would get tax cuts under the plan, a minority of families at every income level would see tax hikes, the Tax Policy Center found.

The analysis suggests that Republicans will have to pull off some dexterous legislating if they want the eventual tax bill to provide no tax cuts for the wealthy and to avoid hitting middle-class families with tax hikes.

"Many individuals will see their taxes increase," said Eric Toder, the co-director of the Tax Policy Center.

Specifically, the analysis finds that taxpayers in the 80th to 95th percentiles, making about $150,000 to $300,000, would see tax increases as a group when the plan is phased in. Those people "might be considered upper-middle class," Toder said.

Speaking Friday on CNBC, White House National Economic Council Director Gary Cohn said the administration uses a "very wide" definition of "middle-class," including people making up to $160,000.

Furthermore, the Tax Policy Center analysis found that some people, across the income scale, would see tax increases. About 1 out of every 9 tax filers in the middle-fifth would see a tax hike, on average a $1,000 hit.

That's because they would be losing some of their itemized deductions, such as the deduction for state and local taxes, as well as personal exemptions. To offset those tax increases, the plan includes a doubled standard deduction and bigger child tax credits. The details that have been spelled out thus far, though, don't clearly indicate that those provisions are big enough to offset the lost deductions and exemptions.

Rep. Kevin Brady, the chairman of the House Ways and Means Committee who will be responsible for writing the legislation, has said the bill will lower taxes at every income level.

Cohn, however, has said that he can't guarantee that every individual in every state will get a tax cut.

Meanwhile, the average tax unit in the top 0.1 percent, earning more than $3.4 million, would receive a boost in after-tax income of more than 10 percent, the biggest such gain along the income spectrum. The average tax cut for that group would be about $723,000.

Meanwhile, the tax reform framework includes language stipulating that the ultimate legislation will make the tax code more progressive than it is today, meaning that it will benefit lower-income earners more than the rich, showing how much work the tax-writing committees have cut out for them.

Trump advisers have criticized the Tax Policy Center and its reports in the past.

On Friday, Brady faulted the report for making "overreaching and unrealistic" assumptions about how Republicans would write the legislation. "This so-called study is misleading, unfounded, and biased," he said in a statement.