Shanahan ran after the officials and reportedly berated them in the tunnel after the game.
ESPN 980 reported that Shanahan said: "You have no (expletive) balls, you are a (expletiving, expletive.)"
(We had to get creative there, but we'll let you fill in the blanks.)
Dan Steinberg of The Washington Post has a number of screen captures of the incident. Shanahan was furious after a late-game unsportsmanlike-conduct call that went against him. The officials badly botched the sequence ending the game.
At least one official said the game was over and there was a 10-second run-off after a Redskins penalty with seven seconds left, but they didn't know the rules. Marvin Lewis and the Bengals started to come out on the field, but eventually the mistake was corrected. Kyle Shanahan was penalized for something he said while arguing for the correction.
Once they announced the penalty on Shanahan, the officials spotted the ball incorrectly by 5 yards, according to Jason Reid of The Washington Post.
UPDATE: Shanahan released a statement Monday, according to The Associated Press, in which he said he acted "in the wrong way" during Sunday's game.
"When I overheard the official tell the head coach that the game was over after the false-start penalty, I tried to explain that the game was not over," Shanahan's statement read. "That is what resulted in the unsportsmanlike-conduct penalty. I tried to get an explanation of how I could get that penalty when half of the other team was on the field as well.
"I was frustrated, and in the process of trying to get some answers from the officials, I conducted myself in the wrong way. I ask our players to hold themselves to a high standard and be accountable, and I know that I'm accountable for my actions as well. I know that I need to handle those situations better in the future. My emotions got the best of me, and I know it's my responsibility. This will never happen again."