NEW YORK: Donald Trump on Wednesday shook up his campaign team for the second time in two months, fending off suggestions that his presidential run is in crisis as polls show Hillary Clinton cruising towards victory.

The Republican White House nominee, who is tanking in key swing states, hired a conservative news executive once dubbed “the most dangerous political operative in America” as his campaign CEO and promoted a leading Republican strategist to campaign manager.

The CEO is Stephen Bannon, executive chairman of the hugely influential and ferociously anti-Clinton conservative website Breitbart News, and the new manager is leading Republican pollster Kellyanne Conway.

“I am committed to doing whatever it takes to win this election, and ultimately become president,” the New York billionaire announced.

The shake-up comes with the campaign set to launch its first major television ads this week and with chairman Paul Manafort under fire in the press after being named in a Ukrainian corruption scandal.

Trump languishes six points behind Clinton -- 47.3 percent to 41.2 percent, according to the Real Clear Politics polling average, and trails her in virtually every key battleground state, raising the prospect of a Clinton landslide win.

The Republican nominee was badly damaged after denigrating the parents of a Muslim American soldier killed in Iraq, and accused last week of inciting violence against Clinton in a remark about the right to bear arms.

A string of prominent Republicans have announced they will not be voting for Trump as US newspapers report of a campaign in crisis and staffers unnerved by a candidate apparently incapable of reeling in crass remarks.

While his media-saturated, populist, outsider campaign fended off 16 rivals to win the Republican nomination, Trump has batted aside suggestions that he should change tack to win the November election from the center.

“I don't wanna change,” Trump told Wisconsin news station WKBT-TV.

“Everybody talks about, 'Oh well, you're gonna pivot'... I don't wanna pivot. I mean you have to be you. If you start pivoting, you're not being honest with people.”

'Street fighter'

Bannon will oversee campaign staff and operations and “strategic oversight of major campaign initiatives,” the Trump campaign said.

Conway will focus on “messaging”, regularly travelling with Trump while also working closely with Manafort and Bannon, the statement said.

It is the second personnel shake-up at the top since June 20 when Trump dropped his first manager, Corey Lewandowski, who was sidelined by Manafort and courted controversy after allegedly grabbing a Breitbart reporter.

Bannon, a former naval officer and investment banker, is seen as a maverick and vehemently anti-Clinton.

An October 2015 profile by Bloomberg Politics described him as “the most dangerous political operative in America.” He is “a bit of a street fighter, willing to go right at his opponents, and make sure that they know that in politics, all is fair,” Lewandowski told CNN.

Bannon's arrival will be seen, at least by some, as a demotion of Manafort, the seasoned Republican advisor returning to presidential politics for the first time in 20 years after working as a lobbyist for controversial clients.

Chief among those clients was Viktor Yanukovych, the pro-Kremlin former president of Ukraine whom Manafort helped rebrand until he was deposed during a popular uprising in 2014.

The head of Ukraine's newly formed National Anti-Corruption Bureau said this week that more than $12 million was earmarked for payment to Manafort from 2007 to 2012, although it was not clear if he received the money.

In an interview with Fox News, Trump claimed that the polls were getting closer and, when asked if he imagined running for president as a child, he deployed some of the populist candor that his supporters admire.

“No, I didn't. If I did, I would have been less controversial,” he said.

On Tuesday, Trump made his first substantial pitch to African American voters of the campaign, telling a rally in Wisconsin that Democrats had “betrayed” them and promised to revitalize impoverished urban communities.

Blacks tend to vote Democrat and voted overwhelmingly in favor of Clinton at the expense of her former party challenger for the nomination, Bernie Sanders.

On Tuesday, Trump also promised to reject bigotry “in all forms” -- another departure for a nominee who previously vowed to ban Muslim immigrants.