(Reuters) - Mort Sahl, who strolled onstage with a newspaper and shook up the comedy world in the 1950s and '60s with a groundbreaking critical look at American life and politics, died on Tuesday at the age of 94, the New York Times and Washington Post reported.

Sahl, who was widely considered the father of modern political satire, died at his home near San Francisco, the newspapers cited a friend as saying. She did not give a cause of death. Reuters could not immediately independently confirm the death.

Sahl was credited with influencing comedians such as George Carlin, Woody Allen and Jonathan Winters. He was also a friend of another comedy mold-breaker, Lenny Bruce, although his act did not include profanity as Bruce's did.

His "Mort Sahl at Sunset," released in 1955, was the first stand-up comedy album and three years later, he had a Broadway show.

Morton Lyon Sahl was born in Montreal on May 11, 1927, and grew up in Los Angeles. He graduated from the University of Southern California, and moved to the San Francisco area in the early 1950s to try comedy. He lived in his car part of the time before building a following at San Francisco's legendary hungry i nightclub and then going on the road.

By 1960, Sahl had become so popular that Time magazine, which called him "Will Rogers with fangs," put him on its cover - the first time a comedian had ever been so honored.

Sahl's stage presence was different from the standard of the 1950s. He dressed informally in V-neck sweaters and was more irreverent, more intellectual, more hip and less rehearsed than his coat-and-tie contemporaries spouting mother-in-law jokes.

Sahl took the stage with a newspaper and only an outline of an act while perching on a stool and relying on improvisation and responding to his audience. He would read from the newspaper to launch his comic riffs on the day's events with a quick-fire delivery that earned him the nickname "Rebel Without a Pause." He simply declared: "Onward" when he was ready to change topics.

"It wasn't that he did political comedy - as everyone keeps insisting," Allen was quoted as saying in the book "Seriously Funny: The Rebel Comedians of the 1950s and 1960s."

"It was that he had genuine insights. He made the country receptive to a kind of comedy it wasn't used to hearing. He made the country listen to jokes that required them to think," said Allen, the filmmaker and comedian.

As Sahl often told his audience: "I don't tell jokes. I give little lectures."

'A DISTURBER'

Sahl described himself to the New York Times in 2004 as a populist, a Puritan, a dreamer and a "disturber." He would ask his audiences: "Is there any group I haven't offended yet?" and he spared neither Republican nor Democrat.

"(John) Kennedy is trying to buy the country and (Richard) Nixon is trying to sell it," he said.

He would later mock Republican President George H.W. Bush as wishy-washy by saying: "God bless George Bush - long may he waver," and later used the same line on Democrat Bill Clinton.

He kept it up through the rise of Donald Trump. "I was on stage last night and I gave a medical report about Donald Trump," he said in an interview with the Library of Congress. "I said he was hospitalized for an attack of modesty."

Before that, Sahl liked to blast Senator Joe McCarthy and the House Un-American Activities Committee for their pursuit of communists.

"If you were the only person left on the planet, I would have to attack you," Sahl said. "That's my job."

Sahl was closely linked with President John F. Kennedy. At the request of Kennedy's father, Sahl had written jokes for him to use while campaigning in 1960, but he later made acerbic jokes about the Kennedy family. Club owners then refused to book Sahl because they had been threatened with tax audits, according to the book "Revel With a Cause: Liberal Satire in Postwar America."

Sahl became obsessed with Kennedy's 1963 assassination. His attacks on the Warren Commission Report, which concluded that Lee Harvey Oswald acted alone in killing the president, became a big part of his act, including readings from the report, turning off his audiences and damaging his career.

He joined New Orleans District Attorney Jim Garrison in investigating assassination conspiracy theories and said he believed the same entity was responsible for the assassinations of Kennedy, his brother Robert and civil rights leader Martin Luther King Jr..

Sahl partially rebounded in the 1970s as non-traditional comedians such as Carlin and Richard Pryor broke through. In 1988, he had a one-man off-Broadway show titled "Mort Sahl's America."

Even in his 90s, Sahl performed weekly at a theater near his Mill Valley, California, home, with the shows being livestreamed on the internet. He had been a close friend of Robin Williams, who lived nearby, before the comic actor's suicide in 2014.

(Reporting by Bill Trott; Additional reporting by Jill Serjeant; Editing by Peter Cooney)