Watergate break-in 'silly,' Nixon told grand jury

Nixon, speaking 10 months after being forced out of the White House in 1974, also recounted how he became enraged when he learned about an 18.5 minute gap in a key tape recording.

The details were included in the transcripts of two days of grand jury testimony from June 1975, released by the Nixon presidential library in California yesterday in response to a legal challenge.

Nixon described his anger on learning that a long section had been erased from an audio recording of a post-Watergate White House meeting, which could have been key in showing what he knew about the Watergate break in.

"I practically blew my stack," Nixon -- known as "Tricky Dicky" -- said, before going on to question whether the tape was needed to be handed over to investigators, as subject to a subpoena.

Nixon resigned in August 1974 for his administration's role in a June 1972 burglary of the Democratic National Committee headquarters at the Watergate complex in the US capital and the subsequent cover-up. He became the only US president ever to do so.

In other testimony, the late ex-president, who died in 1994, lamented the actions of Patrick Gray, acting head of the Federal Bureau of Investigation (FBI), who was initially in charge of investigating the Watergate break-in.

"I believe it is tragic that at this time of this silly, incredible Watergate break-in, he took the papers from Hunt's safe and burned them," he said, referring to Howard Hunt, one of the White House "plumbers" who engineered the Watergate break-in.