NEW YORK - Republican Party presidential front-runner Donald Trump said Sunday he would rescind President Barack Obama’s executive actions on immigration and deport all undocumented immigrants in the US — estimated to number 11.7 million — if elected president. 

Speaking to NBC’s “Meet the Press” news programme,  the billionaire businessman Trump said he would “make a whole new set of standards” to replace Obama’s immigration orders which, subject to court battles, would protect up to 5 million undocumented children and family members from deportation. During the interview, Trump was asked: “So you’re going to split up families? You’re going to deport children?”

“No, no,” he answered. “We’re going to keep the families together. We have to keep the families together, but they have to go.” Asked “what if they have no place to go”, Trump said: “We will work with them. They have to go. We either have a country, or we don’t have a country.” He also said “we have to make a whole new set of standards” for immigration to the US. Trump began his campaign with a controversy on immigration, when at his launch in New York in June he accused Mexico of sending criminals and “rapists” to the US. Despite losing a number of commercial deals because of the comments, he did not back down and has since repeatedly promised to build a wall on the southern US border.

On Saturday NBC also published a document entitled “Immigration reforms that will make America great again”, which it said outlined Trump’s proposals for immigration reform, including a promise to “put America’s workers first”. The five-page document - which later appeared to have been deleted from Scribd.com - also repeated Trump’s call for a wall, to be paid for by Mexico because “in short, Mexico has taken the United States to the cleaners”.

The document referred to crimes committed by illegal immigrants, a favourite Trump subject on the campaign trail. In this instance, the policy document referred to a case in Santa Maria, California in which it said “an illegal immigrant, from Mexico, with a long arrest record” broke into a 64-year-old woman’s home before “crushing her skull and eye sockets with a hammer, raping her and murdering her”.

Trump has also questioned the war record of the senior Republican Senator John McCain, prompting strong attacks from the rest of his party’s field, and, last week, appeared to suggest the Fox News anchor Megan Kelly was menstruating when she asked him tough questions during the first Republican debate. For that, he was uninvited from the conservative RedState Gathering in Atlanta. His unrepentant response has included predictions that, in two sections of the voting populace that traditionally lean Democratic, he will both win the Latino vote, and be “so good to women” as president.

As the leader in polls of the 17-strong Republican field, Trump took centre stage in that first debate, pushing establishment favourite Jeb Bush and other leading contenders such as Marco Rubio and Scott Walker away from the spotlight. Despite near-universal condemnation of his behaviour, and consternation within the Republican party over the damage he may be doing to its chances of taking back the White House, he has maintained a strong position since.

On Saturday he flew into the Iowa State Fair, in Des Moines, by helicopter, prompting joy among his fans and, among Democratic candidates, a glance from Democratic frontrunner Hillary Clinton and a wry joke from Bernie Sanders, who is challenging Mrs. Clinton. Earlier in the week, a poll of likely Republican caucus-goers showed that he had expanded his lead in the crucial, early voting state.