NEW YORK: Donald Trump went on a blistering offensive against Hillary Clinton on Wednesday, calling her a “world-class liar” who is unfit to run for president and savaging her record on trade, foreign policy and immigration.

The Republican White House hopeful, who has denounced Clinton's $42 million war chest as “blood money,” launched his assault on the polarizing presumptive Democratic nominee after weeks of disastrous headlines have fueled speculation that his controversial campaign is unravelling.

Related: Emotional Clinton angrily denies Benghazi cover-up

“Hillary Clinton may be the most corrupt person ever to seek the presidency,” he said in a speech at Trump SoHo, his five-star hotel in Manhattan to shouts of “Trump, Trump, Trump” from supporters.

His attack came one day after Clinton launched her own assault on the Republican, calling him a “dangerous” businessman whose lack of plan to bring back jobs threatened to return America into recession.

Trump's speech, which he read from a teleprompter, signalled a new tone in his battle to win the general election in November, toning done his offensive remarks against Muslims and reaching out to independent voters.

He said the stakes could not be higher, painting himself as an innovative thinker who would protect working Americans from a system rigged against them by career politicians, such as Clinton.

Trump attacked Clinton as a “world-class liar” who “perfected the politics of personal profit and theft” and who lacked the judgment to be America's first woman commander-in-chief.

“She ran the State Department like her own personal hedge fund -- doing favors for repressive regimes, and many others, in exchange for cash,” he alleged of her tenure as America's top diplomat.

Related: Hillary Clinton: Rock-star diplomat or future head of state?

Destabilize Middle East

Trump claimed that her “disgraceful” foreign policy had cost America “thousands of lives and trillions and trillions of dollars” in reference to her support for the invasions of Afghanistan and Iraq.

“In just four years, secretary Clinton managed to almost single-handedly destabilize the entire Middle East,” he added, calling the Islamic State extremist group a threat because of her decisions.

The 70-year-old Trump even sensationally alleged that the US ambassador to Libya, Chris Stevens, who died in an attack on the consulate in Benghazi in 2012, was one of the victims of her decisions.

“He was left helpless to die as Hillary Clinton soundly slept in her bed,” he said. “Her decisions spread death, destruction and terrorism everywhere.” On the economy, he assaulted her support for trade deals, saying they had wrought “total devastation” for working Americans and cost the country nearly a third of its manufacturing jobs.

America's trade deficit with China soared by 40 percent while she was secretary of state, he said: “Hillary Clinton gave China millions of jobs and in exchange Hillary Clinton got rich.” He urged supporters of

Bernie Sanders, Clinton's rival for the Democratic nomination, to join his campaign in taking up their fight against big businesses and to put the worker first.

Trump also rowed back from months of offensive remarks against Muslims, whom he has said should be banned from entering the United States in the wake of terror attacks at home and overseas.

Related: Donald Trump calls for keeping Muslims out of US

He said the Islamic State group in Syria had victimized “peaceful Muslims across the world... who only want to raise their kids in peace and safety.”