The annual gathering not far from the White House brings together journalists, government officials, politicians and media personalities for what's usually an evening of light-hearted banter and celebrity gawking.
Six journalists, including Associated Press White House Correspondent Julie Pace, were to be awarded prizes for their coverage of the presidency and national issues.
The New Yorker's Ryan Lizza won the Aldo Beckman Award, which recognizes excellence in the coverage of the presidency.
Pace won the Merriman Smith Award for a print journalist for coverage on deadline.
ABC's Terry Moran was the winner of the broadcast Merriman Smith Award for deadline reporting.
Reporters Jim Morris, Chris Hamby and Ronnie Greene of the Center for Public Integrity won the Edgar A. Poe Award for coverage of issues of national significance.
With files from The Associated Press