The NFL warned its teams Monday that it will begin levying "significant discipline" to anyone engaging in offensive conduct or contact against game officials, responding to a series of incidents that had grown increasingly worrisome to the NFL Referees Association.

The message was delivered Monday via a memo written by NFL executive vice president Troy Vincent. In the letter, Vincent wrote: "We want to keep our players on the field. No one wants a penalty or an ejection to determine the outcome of the game. In recent weeks, however, there have been several suspensions and ejections because of contact with, and conduct toward, our game officials. This is not who we are -- as players, as clubs, as the NFL."

In a statement, NFLRA executive vice president Scott Green said: "We appreciate the league expressing its concerns to all clubs about abusive actions, both verbal and physical, toward officials. We would expect that any future actions will be met with appropriate and severe punishment."