Two of Donald Trump's children will not be voting for their father in the New York Republican primary - because they've failed to register.

Both Ivanka and Eric Trump missed the registration deadline for next week's vote.

Donald Trump says they were unaware that would-be voters had to register one year before the vote.

He says they both feel "very very guilty".

Trump's youngest daughter, Tiffany, is a registered Republican in Philadelphia, where she is a student at the University of Pennsylvania.

That leaves only Mr Trump's eldest son, Donald Trump Jr, available to vote for his billionaire dad in the family's home state.