A New York judge on Tuesday temporarily blocked the publication of book written by President Trump's niece that is set to publish in July, CNN reported.

The ruling, issued by Judge Hal B. Greenwald of the New York State Supreme Court is the first legal win for Robert Trump, the younger brother of the President. Robert Trump has sought to block the book by Mary Trump, the President's niece, contending it violates a confidentiality agreement related to the estate of the President's father, Fred Trump.

But Ted Boutrous, the attorney who represents Mary Trump, said the order "flatly violates the First Amendment."

"We will immediately appeal," Boutrous said. "This book, which addresses matters of great public concern and importance about a sitting president in an election year, should not be suppressed even for one day."