Trump gives 'closing argument' on taxes as Senate and House Republicans reach potential agreement The president hosted guests who called on Congress to pass the tax reform bill.

 -- In what administration officials billed as a "closing argument" on tax reform, President Donald Trump used a speech in the grand foyer of the White House Wednesday to amplify voices of Americans he claims will directly benefit from the Senate and House Republican tax reform agreement announced earlier in the day.

Touting his party's tax reform goals, Trump pledged he would "never let bad things happen with respect to the economy of our country," and called upon multiple guests in attendance to personally plea for Congress to push through the tax reform plan — a tactic reminiscent of the events President Barack Obama employed in his public relations campaign to pass the 2010 Affordable Care Act.

Trump also used the announcement to broadcast what he termed "breaking news," saying he had confirmed exactly when Americans would start to feel the effects of the tax bill.

“I'm excited to announce that if Congress sends me a bill before Christmas, the IRS, this is just out. This is breaking news. The IRS has just confirmed that America will see lower taxes and bigger paychecks beginning in February. Just two short months from now,” he said.

The White House says it comes down to lower withholding rates by the IRS, which are set to take effect in February if the GOP passes its tax bill on schedule.

"The IRS will have to readjust their withholding tables in light of the tax cuts so that less is withheld from each paycheck. The new withholding will take effect in February," a White House official said.

The IRS has said it will issue a statement on the issue but has yet to do so. It has not responded to multiple requests from ABC News for comment.

While the president is touting the benefits of the plan, some details of the emerging plan — including the number of tax brackets — have yet to be finalized.

Congressional sources confirm to ABC News that the tax bill will include a repeal of the Obamacare individual mandate. The repeal was originally included in the Senate bill but not the House version.

Republican negotiators from the House and Senate working to merge the two chambers' tax bills into one have reached an agreement "in principle," according to two senior congressional sources who spoke on condition of anonymity.

The sources could not offer specifics about the agreement. One source cautioned that while the outlook is positive the ink is not yet dry on the deal.

Details of the compromise tax bill are starting to come into focus. Sen. John Cornyn, R-Texas, and a second GOP source familiar with the negotiations confirmed to ABC News that the following has been agreed upon:

— 21 percent corporate rate (up from 20 percent, but lower than the current 35 percent) — 37 percent top individual tax rate down from 39.6 percent — $750,000 cap for mortgage interest (up from the House bill's proposal of $500,000)

Top congressional Republicans working on the tax bill met with Trump for lunch at the White House earlier today.

The tax overhaul process has moved at a breakneck pace as Republicans try to pass a massive tax cut for businesses and many American families before Christmas and the end of the year. Many lawmakers and their staffs have been scrambling to digest drafts of the bill and what it means for everyday Americans.

An agreement between the House and Senate would set the stage for votes on the tax bill early next week.

Sources said the preliminary plan is for the Senate to vote first — likely Monday — followed by the House with a goal of having the president sign the measure into law by Wednesday.

There is still much work to be done. The negotiators still need to complete the drafting process, including finalizing the legislative text and working with the Joint Committee on Taxation (JCT) to secure a final score on the bill's cost.

They expect to release a final conference report with full details by the end of the week, one source said.

The president expressed his hope the plan would pass quickly.

"I mean, we are so close right now, so close, in fact, almost I don't want to talk about it," Trump said. "Maybe we shouldn't talk about it. The cynical voices that opposed tax cuts grow smaller and weaker. And the American people grow stronger."

He further used the speech at the White House to insert some political jabs against Democrats, claiming they actually "like" the tax plan "a lot" but refuse to support it for partisan reasons. Trump offered no evidence to support the claim, however.

"We'll have very little Democrat support, probably none," he said. "And that's purely for political reasons. They like it a lot. And they can't say it. They don't like what's happening. But they can't say it. Someday we have to come together and do bipartisan. And hopefully, it can happen soon."

ABC News' Ali Rogin, Mariam Khan and Meridith McGraw contributed to this report.