New York - Two of Donald Trump's children failed to register in time, so won't be able to vote for him during next week's New York primary, the Republican frontrunner said Monday.
Ivanka, 34, and Eric, 32, were "unaware of the rules and... they didn't register in time," Trump told US Fox News television.
"They feel very, very guilty," he added.
"I think they have to register a year in advance and they didn't. So Eric and Ivanka, I guess, won't be voting," he said, joking that he would cut their allowances.
New Yorkers had to register their party affiliation by October 9 last year in order to vote in the April 19 Democratic and Republican primaries.
Ivanka frequently appeared at her father's side on the campaign trail before giving birth to her third child on March 27.
Eric has also been actively involved in Trump's presidential bid, as has 38-year-old Donald Jr., who is a registered Republican.
Trump's fourth child Tiffany, a 22-year-old college student, has not played a major role in the campaign. Barron, the son of Trump and his current wife Melania, is 10.
Trump is seeking a win in his native New York, which has 95 delegates up for grabs, to regain momentum in the race.
Although he maintains a healthy lead in the delegate count, Texas Senator Ted Cruz has been chipping away at the advantage and trying to deny the billionaire the delegates needed for an uncontested nomination at the national Republican party convention in July.
On Saturday, Cruz scored his fourth consecutive win over Trump when he took all 13 delegates at stake in Colorado's state Republican convention.
In the Fox interview, Trump also criticized The Boston Globe newspaper which on Sunday ran a fake front page imagining the state of America under his presidency.
"It's a very sad thing and it's sad for the paper," he said.
"It used to be considered a major paper and now it's like a supermarket throw-out. You take a look at it there's almost nothing in it - there's no ads." The Globe's spoof edition featured the headline "Deportations to begin," above an article about Trump's push to expel more than 11 million undocumented immigrants - sparking nationwide riots and curfews.
Another make-believe piece detailed the meltdown of US trade relations with China and Mexico.
The mockup in the newspaper's idea section ran alongside an editorial titled "The GOP must stop Trump."