We're hearing a rumor that Tim Russert collapsed and died from a coronary while preparing Meet the Press at NBC Studios today.

UPDATE: A source confirms. Russert was transported from the NBC studio in DC to DC's Sibley Hospital at about 2:15 today. A statement from his family should be forthcoming. (Note: Wikipedia puts the time of death at 1:14.)

MSNBC has more.

UPDATE: NBC Universal president Jeff Zucker: "We are heartbroken at the sudden passing of Tim Russert. We have lost a beloved member of our NBC Universal family and the news world has lost one of its finest. The enormity of this loss cannot be overstated. More than a journalist, Tim was a remarkable family man. Our thoughts and prayers are with his wife, Maureen, their son, Luke, and Tim's entire extended family."