The Donald Trump bullet train has charged full speed ahead as the unfiltered United States presidential hopeful slammed China, Barack Obama's administration and Republican rival Jeb Bush while revelling in fresh poll results that he said show him "leading everywhere".
Ignoring warning signs his campaign may be running into trouble, the brash celebrity billionaire held a wide-ranging press conference before a speech in Michigan and lashed out on several subjects but declined to provide policy details.
"We'll be announcing over the next two weeks numbers and specifics," he said when asked of his jobs plan.
Who do you think they were watching, Jeb Bush? ... I don't think so
Donald Trump on the Republican debate
"You have to be flexible on jobs and everything else."
He used his take-no-prisoners style to batter Mr Bush in particular, saying the former Florida governor "will not be able to negotiate against China [or] Mexico".
Mr Trump lit a powder keg during last week's debut Republican presidential debate when he refused to pledge he would not run as an independent, clashed with a popular Fox News moderator and later made comments about her that many interpreted as crudely sexist.
But Mr Trump, himself a former reality TV impresario, said he was responsible for drawing millions to that prime-time debate broadcast.
"Who do you think they were watching, Jeb Bush? Huh? I don't think so," he quipped.
Asked if he would acknowledge he has gone over the top with some of the criticism and his braggadocio, Mr Trump pointed to the polls.
"Leading in Iowa, leading in New Hampshire ... leading in South Carolina, leading in Nevada," Mr Trump said, rattling off several early voting states.
Iowa poll puts Trump ahead with 17pc support
A new Suffolk University poll in Iowa, which holds the first presidential contest early next year, has Trump in the lead with 17 per cent support, Wisconsin governor Scott Walker in second with 12 per cent and senator Marco Rubio of Florida with 10 per cent.
The survey also showed Mr Bush, a one-time frontrunner, slipping to seventh spot.
But in a warning of sorts to Trump, 55 per cent of Suffolk respondents said his debate performance made them "less comfortable" with him as a candidate.
In a new Rasmussen Reports poll, Trump led with 17 per cent — a significant drop from the 26 per cent he enjoyed in the same national poll conducted late last month.
As the new data emerged, Trump doubled down on his assertion that he would not rule out a third-party candidacy — a nightmare scenario for Republicans.
"I want to run as a Republican," he told local media on Tuesday.
"But I do want to keep that door open in case I don't get treated fairly."
Experts stressed an independent Trump candidacy could spell disaster for Republicans because such a move could split the GOP vote and hand election victory to likely Democratic nominee Hillary Clinton.
Trump pushes forward, says US needs 'spirit, cheerleading, jobs'
The former secretary of state meanwhile offered blunt criticism of Trump, saying on Monday he went "way overboard" in his crude verbal assault on a female journalist.
Fox News moderator Megyn Kelly used tough tactics when questioning Trump during Thursday's debate.
A day later Trump said Ms Kelly had "blood coming out of her wherever," a remark many construed as referring to menstruation.
Meanwhile in Michigan, Trump let loose on Beijing, saying something ought to be done to "reign in China" — but again offered no specifics — after its sharp currency devaluation Tuesday, a move he blasted as a "disgrace".
"China has no respect for president Obama whatsoever," he boomed.
"They think we are run by a bunch of idiots."
On domestic race relations, strained by several deaths of unarmed black men at the hands of white police officers, Trump said there were "powder kegs all over the country waiting to explode".
Asked how to improve the situation, Trump offered: "You need spirit, cheerleading and jobs."
Trump, who made disparaging remarks about Mexican immigrants early in his campaign, insisted he would "do well with the Hispanic vote and do great with the women vote".
He noted Mr Bush's recent questioning of the amount of funds needed for women's health will be a "disaster" for his rival.
"The women's health issues, I'm for that," Trump insisted.
"I cherish women.
"I will be great on women's health issues. Believe me."