around 2 percent.

The shocking findings came from a study which is due to be released by conservative think tank the American Action Forum.

The research adds to concerns about the Republican White House nominee's policy proposals, which range from tearing up international trade agreements to building a wall along the U.S. border with Mexico.

About 6.8 million of the more than 11 million immigrants living in the United States illegally are employed, according to government statistics.

Removing them would cause a slump of $381.5 billion to $623.2 billion in private sector output, the Washington-based non-profit said in its analysis.

Trump, who effectively sealed the Republican nomination this week, has called for the deportation of anyone living in the United States illegally, arguing foreign workers hold down salaries and contribute to unemployment

The removalof migrant workers could leave potentially millions of jobs unfilled due to a lack of legal workers willing to do them

Trump has further angered opponents by saying Mexico was sending rapists and drug dealers to the USA

The study added that removing those workers could leave potentially millions of jobs unfilled due to a lack of legal workers willing to do them. Industries with the highest share of undocumented workers include farming, construction, and hospitality, according to the research.

'The things Donald Trump has said are utterly unworkable,' said Douglas Holtz-Eakin, the forum's president, and the top economic adviser to Senator John McCain's 2008 presidential campaign.

Trump, who effectively sealed the Republican nomination this week, has called for the deportation of anyone living in the United States illegally, arguing foreign workers