No further details were immediately available.
Russert, the recipient of 48 honorary doctorates, took over the helm of "Meet the Press" in December 1991. Now in its 60th year, "Meet the Press" is the longest-running program in the history of television.
In 2008, Time Magazine named him one of the 100 most influential people in the world.
In 2005, Russert was awarded an Emmy for his role in the coverage of the funeral of President Ronald Reagan. His "Meet the Press" interviews with George W. Bush and Al Gore in 2000 won the Radio and Television Correspondents' highest honor, the Joan S. Barone Award, and the Annenberg Center's Walter Cronkite Award.
Russert joined NBC News in 1984. In April 1985, he supervised the live broadcasts of NBC's "TODAY" show from Rome, negotiating and arranging an appearance by Pope John Paul II, a first for American television. In 1986 and 1987, Russert led NBC News' weeklong broadcasts from South America, Australia and China.
Russert was born in Buffalo, N.Y., on May 7, 1950. He was a graduate of Canisius High School, John Carroll University and the Cleveland-Marshall College of Law. He was a member of the bar in New York and the District of Columbia.
Before joining NBC News, Russert was counselor in the New York governor's office in Albany in 1983 and 1984 and a special counsel in the U.S. Senate from 1977 to 1982.
Russert wrote two books - "Big Russ and Me" in 2004 and "Wisdom of Our Fathers" in 2006 - both of which were New York Times best-sellers.
Russert's March 2000 interview of Sen. John McCain shared the 2001 Edward R. Murrow Award for Overall Excellence in Television Journalism. He was also the recipient of the John Peter Zenger Award, the American Legion Journalism Award, the Veterans of Foreign Wars News Media Award, the Congressional Medal of Honor Society Journalism Award, the Allen H. Neuharth Award for Excellence in Journalism, the David Brinkley Award for Excellence in Communication and the Catholic Academy for Communication's Gabriel Award. He was a member of the Broadcasting & Cable Hall of Fame.
Russert was a trustee of the Freedom Forum's Newseum and a member of the board of directors of the Greater Washington Boys and Girls Club, and America's Promise - Alliance for Youth.
In 1995, the National Father's Day Committee named him "Father of the Year," Parents magazine honored him as "Dream Dad" in 1998, and in 2001 the National Fatherhood Initiative also recognized him as Father of the Year.
Irish America magazine named him one of the top 100 Irish Americans in the country, and he was selected as a Fellow of the Commission of European Communities.
Russert is survived by his wife, Maureen Orth, a writer for Vanity Fair magazine, and a son, Luke.
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