Daniel Ellsberg, a US government analyst who became one of the most famous whistleblowers in world politics when he leaked the Pentagon Papers, exposing US government knowledge of the futility of the Vietnam war, has died. He was 92. His death was confirmed by his family on Friday.

In March, Ellsberg announced that he had inoperable pancreatic cancer. Saying he had been given three to six months to live, he said he had chosen not to undergo chemotherapy and had been assured of hospice care.

"I am not in any physical pain," he wrote, adding: "My cardiologist has given me license to abandon my salt-free diet of the last six years. This has improved my life dramatically: the pleasure of eating my favourite foods!"

On Friday, the family said Ellsberg "was not in pain" when he died. He spent his final months eating "hot chocolate, croissants, cake, poppyseed bagels and lox" and enjoying "several viewings of his all-time favourite [movie], Butch Cassidy and the Sundance Kid", the family statement added.

"In his final days, surrounded by so much love from so many people, Daniel joked, 'If I had known dying would be like this, I would have done it sooner …'

"Thank you, everyone, for your outpouring of love, appreciation and well-wishes. It all warmed his heart at the end of his life."

Tributes were swift and many.

Alan Rusbridger, the former editor-in-chief of the Guardian, said Ellsberg "was widely, and rightly, acclaimed as a great and significant figure. But not by Richard Nixon, who wanted him locked up. He's why the national interest should never be confused with the interest of whoever's in power."