Detroit (CNN) Donald Trump sought to get his stumbling campaign back on track Monday, unveiling a tax reform plan aligned with House Speaker Paul Ryan's policy agenda.

Trump's new proposal would reduce tax rates for most Americans and simplify the tax code, but the new rates Trump proposed mark an increase from those he proposed last year as he campaigned for the Republican nomination and touted his tax reform plan as offering the lowest income tax rates of any of his GOP opponents.

Trump's new proposal would more than halve the number of income tax brackets and bring rates down to 12%, 25% and 33%. Trump proposed drastically reducing federal income tax rates to 10%, 20% and 25% -- a proposal that nonpartisan groups assessed would add trillions of dollars to the national debt.

Americans in the top income bracket are currently taxed at 39.6%. Trump also vowed again Monday that the poorest Americans will have a zero tax rate, which he included in his initial proposal.

The Republican nominee, who was interrupted by protestors 14 times, unveiled his economic plan -- which included proposals beyond just tax reforms -- a week after he feuded with Ryan. The real estate mogul initially refused to endorse the speaker, who faces a primary Tuesday. But Trump ultimately backed Ryan on Friday after a tumultuous week of intra-party fighting.

Speaking at the Detroit Economic Club, Trump laid out proposals to achieve an American "economic renewal," including a moratorium on government regulations, a proposal to make childcare expenses fully tax deductible, and other proposals his campaign argued will benefit the middle class.

"It's a conversation about how to make America great again for everyone and, especially, and I say especially, for those who have the very least," Trump said.

Trump's speech, in which he offered detailed policy proposals rarely heard in his typical stump speech, came as the Republican faces steeply declining poll numbers following two bad weeks on the campaign trail during which he repeatedly stoked controversies that distracted from his core campaign message.

But Trump, reading from teleprompters, was laser-focused on promoting his economic agenda and contrasting his plans with Hillary Clinton's. The Democratic nominee is also set to lay out her own economic proposals in Detroit in a major address on Thursday.

Trump pointed to Detroit, a city lately besieged by economic turmoil and run for decades by successive Democratic mayors, as the "living, breathing example of my opponent's failed economic agenda."

Trump called the city's economic collapse an example of politicians abandoning "America first" policies in favor of a globalist agenda.

"If you are a foreign power looking to weaken America, you couldn't do better than Hillary Clinton's economic agenda," Trump said.

But Trump went beyond bomb-throwing, laying out in detail a number of proposals he would seek to enact as president that would reduce the regulatory influence of the federal government, particularly on fossil fuel industries.

He also again vowed to lower the business tax rate for corporations and small businesses alike to 15% -- down from the current top rate of 39%.

"We will make America grow again," Trump said.

On Tuesday, Trump said on "Fox and Friends" that he would also consider a payroll tax holiday to help the middle class. In response to a viewer question, Trump said he's thinking about the concept.

Trump also said he would look to restart the Keystone XL pipeline project, and withdraw the U.S. from the Paris climate agreement, withdraw the U.S. from the Trans-Pacific Partnership and renegotiate the North American Free Trade Agreement, which was enacted by President Bill Clinton.

Ryan's campaign spokesman Zack Roday praised Trump's proposal, saying it "has many similarities to the job-creating plan at the heart of House Republican's Better Way agenda."

"A Better Way," is a plan Ryan introduced in June as speaker that lists changes to six policy areas, including tax reform.

Hillary Clinton offered a direct rebuttal to Trump's remarks during a rally in St. Petersburg, Florida, later in the day.

"He wants to basically just re-package trickle down economics. Now, you know that old saying, 'Fool me once, shame on you, fool me twice, shame on me?' " Clinton said. "Trickle down economics does not help our economy grow. It does not help the vast majority of Americans."

Stressing the importance of the fall election, Clinton urged the crowd: "Don't let a friend vote Trump."

At a family-owned beer brewery earlier in the day, Clinton accused Trump for engaging in the business practice of refusing to pay workers for their services. Clinton said she has met countless people who were "stiffed" by Trump and told: "Just sue us," and drew on her personal experience of having watched her own father run a small print plan as a child.

"He worked really hard and made a good living for my mother, my brothers and me," Clinton said about her father at 3 Daughters Brewing, surrounded by thousands of stacked beer cans and large silver brew houses. "That's why I just can't imagine -- he'd worked so hard -- if he had delivered the finished goods to the people who had ordered them, that they would say we're not going to pay you. And that's what Trump has done time and time again."

Clinton has been pulling away from Trump in recent polling, following his disastrous battle with the Gold Star parents of slain Iraq War veteran Capt. Humayun Khan. The latest CNN Poll of Polls shows Clinton beating Trump 49%-39% nationwide

But a CNN poll in June and a more recent Fox News survey found that voters trust Trump more than Clinton on the economy.

Clinton running mate Tim Kaine tweeted Monday, "Donald Trump is only in it for himself -- just look at his economic plan."