Walter Cronkite is shown Nov. 14, 2006, in Phoenix, Ariz. There are reports he is gravely ill. (Tempe State Press/Christopher Atwood/Associated Press)

Walter Cronkite, 92, the former CBS anchor once known as the Most Trusted Man in America, is reported to be gravely ill.

The news comes from Mediabistro's blog, TVNewser, quoting unidentified sources inside CBS. The U.S. network declined to confirm reports that the legendary newsman is in poor health.

The nature of his illness is unknown, but Newsday reports that Cronkite's memory is failing.

Cronkite was anchor of CBS Evening News for 19 years, ending in 1981 when he handed over the desk to Dan Rather.

His nightly sign-off on the broadcast, "and that's the way it is …" was well-known throughout America.

He remained active as a special correspondent until 2008 and has been an often acerbic commentator on U.S. politics.

As a news anchor when CBS News was in its heyday, Cronkite conveyed to Americans historic events such as the assassination of President John F. Kennedy and the landing of the first man on the moon.

His tenure as anchor stretched from Kennedy to Reagan, and he later interviewed Clinton and heaped scorn on the politics of George W. Bush.

Cronkite's calm and sober style, and CBS's reputation for in-depth journalism, worked together to make him the most trusted source of news in America.

Cronkite was born in 1916 in Missouri and first came to national attention as a war correspondent for United Press during the Second World War.

In 1950, Edward R. Murrow hired him for the CBS Washington bureau. In 1962, he became anchor for CBS Evening News and contributed to making it the top-rated newscast in America.

He retired as anchor in 1981, when he was 65, but continued to contribute to CBS, CNN and NPR.

Cronkite comes from a long-lived family: His father lived to be 100 and his mother to 101. He lost his wife, Betsy, in 2005.