Dallas quarterback Dak Prescott apologized on Tuesday for praising fans who threw trash at game officials after their 23-17 home defeat by San Francisco in the NFC Wild Card game at the weekend.

Asked by reporters what he thought of the fans' actions after his team ran out of time during a late comeback attempt on Sunday, Prescott said "credit to them."

On Tuesday, however, Prescott said he "deeply regretted the comments".

"I was caught up in the emotion of a disappointing loss and my words were uncalled for and unfair," he wrote on Twitter.

"I hold the NFL Officials in the highest regard and have always respected their professionalism and the difficulty of their jobs.

"The safety of everyone who attends a game or participates on the field of a sporting event is a very serious matter.

"That was a mistake on my behalf, and I am sorry."

Prescott and the Cowboys were driving down field late in the fourth quarter but with just seconds to go they were unable to snap the ball before the game clock expired.

Earlier on Tuesday, the National Basketball Referees Association condemned Prescott's comments for "condoning violence against game officials."

"As an NFL leader, he should know better," the association tweeted.

"We encourage the NFL to take action to discourage this deplorable behavior in the future."