DETROIT/WASHINGTON - Republican Donald Trump sought to regain momentum for his White House campaign on Monday by proposing sweeping tax breaks, cuts to federal regulations and a revival of the stalled Keystone XL oil pipeline project.

The New York businessman used an address on the economy to try to turn the page after a week of missteps in which he came under heavy criticism, including from some in his own party, and rival Democrat Hillary Clinton surged ahead in opinion polls with three months to go until the Nov. 8 election.

Trump followed prepared remarks rather than using the free-wheeling style at rallies that has often produced controversial comments. He also kept his cool as some 14 protesters jumped to their feet and shouted at him at intervals as he spoke at the Detroit Economic Club.

Most of the interruptions were at one- or two-minute intervals, giving the appearance of a coordinated effort to rattle him. He was also cheered repeatedly by the crowd.

Trump's remarks appeared targeted at both an affluent business community and working people, in particular those who have suffered from a decline in U.S. manufacturing in cities such as Detroit.

He said his plan would include imposing a temporary moratorium on new federal regulations, reducing rates for income and corporate taxes, and establishing new provisions for working parents dealing with childcare costs.

His tax plan reflected traditional Republican thinking that lowering taxes can generate economic growth and creating jobs.

He proposed a broad package of tax cuts, lowering tax brackets for individuals based on income to 12 per cent, 25 per cent and 33 per cent, and reducing the corporate tax rate from the current 35 per cent to 15 per cent.

He would eliminate the estate tax levied on the assets of the dead, and allow businesses with trillions of dollars of profits overseas to bring the money home with a 10 per cent levy. He would establish new provisions for working parents dealing with childcare costs.

His trade plan went against party orthodoxy but is aimed at helping rebuild what he depicts as a middle-class shattered by job outsourcing in recent decades.

Trump said he would rewrite the landmark NAFTA trade deal that Clinton's husband, then-President Bill Clinton, signed in 1994 linking the economies of the United States, Mexico and Canada. He would also withdraw the United States from the Trans Pacific Partnership trade deal backed by President Barack Obama.

He would also bring back the Canada-to-Texas Keystone oil pipeline project that Obama has turned down.

"We now begin a great national conversation about economic renewal for America. It's a conversation about how to make America great again for everyone...especially for those who have the very least," he said.

Trump's effort to shift the focus came after what was widely viewed as the worst week of his presidential campaign and included strong attacks by critics on his temperament and suitability for the White House.

On Monday, Trump waited for the frequent disruptions by protesters to end, smiling and refraining from his practice at campaign rallies of asking security to "get them out of here."

A group called the Michigan People's Campaign took credit for the protests, which were aimed at Trump's recent comments about sexual harassment.

"You'll have to answer to women, Mr. Trump," one woman shouted.

Clinton is to outline an economic vision of her own in Michigan on Thursday. In a statement ahead of Trump's speech, her campaign said his plan would give tax breaks to the wealthy and big companies, and would hurt working families and trigger a recession.

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Trump, a real estate developer who has never held elected public office, touts his practical experience on economic matters and potential to create jobs, blaming President Barack Obama for what he calls a weak recovery from the economic recession. On Monday, he repeatedly described Clinton as a candidate who would rely on policies that have not worked.

"She is the candidate of the past," Trump said. "Ours is the campaign of the future."

Reaction from the crowd was mixed. Some liked his message, such as insurance executive Sal Giammursta.

"There were too many protesters. But I think he laid out a good bullet point on how he's going to solve the economic problems with his trade policies," he said.

Others wanted more details.

"People were looking for more substance," said lawyer Al Rogalski.

Another participant, Tiffany Douglas, agreed.

"A lot of what, no how. I don't care what he thinks about Hillary. What's about what he's going to do?" she said.

The Detroit speech was Trump's first on the economy since he announced a 13-man team of economic advisers late last week. The group held its first conference call on Sunday.

"He's trying to rebuild momentum after his serious stumbles over the past 10 days," said Ron Bonjean, a Republican strategist in Washington. "This is to target voters in general that he's not just live-tweeting his candidacy, that there is some deeper thought behind his efforts."

Trump got entangled last week in days of dispute with the parents of a Muslim American soldier who was killed in the Iraq war, and sparred with party leaders. Frustrated Republicans plan to put forth a conservative alternative to Trump, former top House aide and former CIA officer Evan McMullin.

Trump's rough ride took its toll in opinion polls. A Washington Post-ABC News poll released on Sunday gave his Clinton an eight-point lead, 50 per cent to 42 per cent.