Up to 11 million illegal immigrants living in the US could face immediate deportation if Donald Trump wins the November election for the White House.

The GOP candidate announced during a fiery speech on immigration on 31 August in Arizona that there would be 'no amnesty' for those who had been living and working undocumented in the US – with those under threat most likely to be Mexicans living in US border states.

Trump declared: "For those here today illegally who are seeking legal status, they will have one route and only one route: to return home and apply for re-entry under the rules of the new legal immigration system that I have outlined above. Those who have left to seek entry under this new system will not be awarded surplus visas, but will have to enter under the immigration caps or limits that will be established.

"We will break the cycle of amnesty and illegal immigration. There will be no amnesty. Our message to the world will be this: you cannot obtain legal status, or become a citizen of the United States, by illegally entering our country. This declaration alone will help stop the crisis of illegal crossings and illegal overstays. People will know that you can't just smuggle in, hunker down, and wait to be legalised. Those days are over."

The US Department of Homeland Security's Office of Immigration Statistics from 2012 estimate there are up to 11 million people living illegally in the US.

The majority (71%) of people believed to be living in the US illegally hail from Mexico, with 54% of 'illegal aliens' believed to be living in just four states; Florida, California, Texas and New York, according to MigrationPolicy.org.

But Trump's proposed discontinuation of the amnesty programmes that allow 'illegal aliens' to remain in the US legally, will be alarming particularly for those people who have lived in the US for years and have established families, jobs and lives there.

And given the impact Trump's policy on immigration would have on Mexican immigrants to the US, Mexican President Enrique Pena Nieto has spoken out against the GOP candidate's views.

"His policy stances could represent a huge threat to Mexico, and I am not prepared to keep my arms crossed and do nothing," Pena Nieto stated in a TV interview quoted by The Telegrapgh.

"That risk, that threat, must be confronted. I told him that is not the way to build a mutually beneficial relationship for both nations."

Pena Nieto's comments come after an apparently agreeable meeting between him and Trump in Mexico City.