Donald Trump has said he would cut off money sent to Mexico to force them to pay for a border wall with the US.
In a memo to the Washington Post, the Republican presidential hopeful says he would threaten to change a law to cut off cash transfers.
The prospect of losing a vital source of income would force Mexico into a “one-time payment” of $5-10 billion, says Donald Trump.
Voters in Wisconsin are picking their presidential candidates.
They are going to the polls in a vote that could reshape the Republican race, with front-runner Donald Trump facing a strong challenge from Texas Senator Ted Cruz.
Asked about the memo at a campaign stop in Wisconsin, Donald Trump said he stood by it.
“Absolutely, 100%,” he told reporters.
“The wall is a fraction of the kind of money in many ways that Mexico takes from the US.”
Building a border wall with Mexico has been a core message of Donald Trump’s campaign but until now he has not said in much detail how he would make Mexico pay for it.
Mexico’s central bank said that money sent home from overseas hit nearly $24.8 billion in 2015, more than its oil revenues.
The law Donald Trump wishes to changes, as outlined in his memo, is part of the US Patriot Act – he would stop anyone living illegally in the US from sending money overseas.
Just the threat of enacting this would make Mexico “immediately protest,” the Trump memo reads, and they would be compelled to pay for the wall.
Donald Trump also proposed raising visa fees and cancelling visas for Mexicans.
If Ted Cruz wins in Wisconsin, as polls suggest, it will help him close the gap on Donald Trump in the all-important delegate count.
Delegates represent their states at the GOP’s convention in July and are accumulated by the votes in each state.
A Wisconsin defeat would make it is far less likely that Donald Trump will have the 1,237 delegates needed to secure the nomination.
It would raise questions about the strength of his campaign, after a week of adverse headlines.
Donald Trump’s unpopularity with sections of his party means he could be deprived of the nomination at the summer convention if he does not get the number he needs.
Currently, Donald Trump has 735 delegates, Ted Cruz 461 and Ohio Governor John Kasich 143.