Donald Trump and his sister, Maryanne Trump Barry

US President Donald Trump's older sister, a former federal judge, has said her brother is a liar who "has no principles". Trump's sister confessions have come to light from some secret recordings.

Criticism of Marianne Trump Barry was recorded by her granddaughter, Mary Trump, who last month published a book exposing the president.

"His Twitter posts and his lies ... Oh God! Pretend and cruelty," Barry is heard to say.

Mary Trump said she had eavesdropped on her aunt to defend herself from litigation.

As Donald Trump responded to recent publications in a statement issued by the White House, saying: "Every day is something else, who cares ..."

The recordings were first published by The Washington Post and later by the Associated Press.

One of the claims made in Mary Trump's book, "Too Much and Never Enough: How My Family Created the World's Most Dangerous Man," is that her uncle, Donald Trump, paid a friend to take the SAT exam for him - a standardized exam that determines university entrance.

"He went to the University of Pennsylvania because he had someone who took the exams for him," Berry said in one of the recordings, adding that he also knew the name of the person who took the exam instead of Trump.

Adapted from BBC