The NBC's Washington Bureau Chief collapsed at work and was immediately taken to the Washington's Sibley Memorial Hospital, where he died at 58, the hospital confirmed.

At hearing the news, President George W. Bush sent condolence from Italy to Russert's family, saying he was a tough and hardworking newsman.

"He was an institution in both news and politics for more than two decades," Bush said in a statement. "He was always well-informed and thorough in his interview."

Both of two presidential candidates, Barack Obama and John McCain, who have appeared in TV debates Russert moderated, expressed their sorrow at Russert's death.

Born in 1950 in Buffalo, New York state, Russert won a law degree and has served as an aide to a late Democratic Senator. He joined the NBC in 1984 and took the helm of "Meet the Press" in December 1991. Under his watch, the program became one of the most widely watched of its type in the United States and he also established himself as the face of the network's political coverage.

Apart from "Meet the Press," Russert also appeared in many other news shows, hosted numerous political debates and wrote two best-selling books.

In 2008, he was named by the Time Magazine as one of the 100 most influential people in the world.