The final installment of secret recordings from President Richard Nixon's White House captures future president Ronald Reagan calling to offer support after Nixon delivered a public address on Watergate.
The April 30, 1973, phone conversation was released Wednesday along with 340 hours of tape and more than 140,000 pages of documents.
Reagan, then California governor, called Nixon in the late evening after he had delivered a speech as the Watergate crisis picked up speed.
Earlier that day, two top White House staffers and the attorney general had resigned and the White House counsel was fired.
Reagan reassures Nixon of his support and says the speech was on target.
The tapes also include recordings of Nixon and Soviet leader Leonid Brezhnev chatting warmly in the Oval Office before a historic summit.