NEW YORK (AFP) - John F. Kennedy carried on an 18-month-long affair with a teenaged White House intern, according to a new book by the woman who claims to have been the late United States president's lover.

Excerpts of the shocking memoir, Once Upon A Secret: My Affair With President John F. Kennedy And Its Aftermath, were released on Monday by the New York Post, which said it purchased a copy of the book at a local bookstore, although it is not scheduled for publication until Wednesday.

In her tell-all memoir, author Mimi Alford, now a 69-year-old grandmother, recounts the president's tears after the death of his newborn son, and recalls that he confided to her, while embroiled in the drama of the Cuban missile crisis that 'I'd rather my children red, than dead.' Alford provides intimate details of their relationship, which started in the summer of 1962, when she was just 19, less than half the age of the dashing president, who was killed the following year by an assassins' bullet at the age of 46.

In an excerpt published by The Post, Alford wrote that she met Kennedy just four days into her internship, and that he invited her the following day on a personal tour of the White House residence that included first lady Jackie Kennedy's bedroom.