The White House is staying mum ahead of President Trump’s announcement of his much-anticipated tax plan Wednesday, but top congressional Republicans sounded open Tuesday to big cuts even if they add trillions to the deficit.

"I'm not convinced that cutting taxes is necessarily going to blow a hole in the deficit," said Utah GOP Sen. Orrin Hatch, chairman of the Finance Committee.

Later in the day, Hatch met on Capitol Hill with Treasury Secretary Steve Mnuchin and other top White House officials.

They were scheduled to be joined by Senate Majority Leader Mitch McConnell, R-Ky., House Speaker Paul Ryan, R-Wis., and others.

The meeting was also expected to include Gary Cohn, chief of the White House Council of Economic Advisers, and House Ways and Means Committee Chairman Kevin Brady, R-Texas.

On Wednesday, Trump is expected to announce a tentative tax plan that could lower the top corporate tax rate from 35 percent to 15 percent.

The president unexpectedly said Friday he’d announce a plan this week, amid a few hectic days on Capitol Hill, as lawmakers try to pass a spending bill to avert a government shutdown.

Trump said the cuts to individuals and companies would be “massive,” as his first 100 days in office end Saturday.

On Tuesday, White House Press Secretary Sean Spicer repeatedly deflected reporters’ demands for more specifics.

“I think tomorrow we’ll have a great plan for you to see,” he said. “We’ll have plenty of time to talk to you about that tomorrow.”

However, his remarks followed several top White House officials earlier in the week test driving the proposal.

Mnuchin said Monday that the plan will include tax cuts for “middle-income” Americans and will simplify the U.S. tax code.

“The average American should be able to do his taxes on a large post card,” he also said.

On Sunday, White House budget director Mick Mulvaney told Fox News that Trump would likely talk about proposed tax rates and said a final plan likely wouldn’t be complete until June.

Republicans slammed the growing national debt under Democratic President Barack Obama.

The argument that tax cuts pay for themselves has been debunked by economists from across the political spectrum. On Tuesday, the official scorekeeper for Congress dealt the argument -- and Trump's plan -- another blow.

The nonpartisan Joint Committee on Taxation said that a big cut in corporate taxes -- even if it is temporary -- would add to long-term budget deficits. This is a problem for Republicans because it means they would need Democratic support in the Senate to pass a tax overhaul that significantly cuts corporate taxes.

"Now, whether 15 percent is the right figure or not, that's a matter to be determined," Hatch said.

The assessment was requested by Ryan, who has been pushing a new tax on imports to fund lower overall tax rates. Senate Republicans have panned the idea, and officials in the Trump administration have sent mixed signals about it.

The import tax is not expected to be part of Trump's plan.

No Democrat was invited to the Capitol Hill meeting.

"Today's Democratic Party seems to be preoccupied with wealth transfer from those who have done well to those who have done less well," McConnell said. "That's unrelated to having a set of tax laws that promote growth."

Republicans have been working under a budget maneuver that would allow them to pass a tax bill without Democratic support in the Senate -- but only if it didn't add to long-term deficits.

McConnell said the Senate was sticking to that strategy.

"Regretfully we don't expect to have any Democratic involvement in" a tax overhaul, McConnell said. "So we'll have to reach an agreement among ourselves."

Democrats said they smell hypocrisy over the growing national debt, which stands at nearly $20 trillion. For decades, Republican lawmakers railed against saddling future generations with trillions in debt.

But with Republicans controlling Congress and the White House, there is no appetite at either end of Pennsylvania Avenue to tackle the long-term drivers of debt -- Social Security and Medicare. Instead, Republicans are pushing for tax cuts and increased defense spending.

"I'm particularly struck by how some of this seems to be turning on its head Republican economic theory," said Sen. Ron Wyden of Oregon, the top Democrat on the Senate Finance Committee.

Still, the Trump administration on Tuesday stuck with its assertion that tax reform could push economic growth above 3 percent. Commerce Secretary Wilbur Ross said that the combination of changes on taxes, trade and regulations being pushed by the administration would accelerate the pace of economic gains.

"There is no reason that we should not be able to hit that -- if not beat it," Ross said at the White House news briefing.

The Associated Press contributed to this report.