According to the Washington Post, RNC chair Reince Priebus is keeping an eye on Donald Trump. The Chairman reportedly called Trump to tell him to "tone down his inflammatory comments that have infuriated a key election constituency."

And Priebus isn't the only one.

The Post cites former senator Robert F. Bennett (R-Utah) who says "if Trump can keep this going, it will be truly worrisome."

Someone described only as a Republican state chairman said, “[Trump has] already done some damage, and it could be substantial going forward. He could be one of the reasons we lose. It’s that serious. There’s nothing we can do about it, and that’s what’s so scary.”

The Post says about the phone call with Priebus, it "underscores the extent to which Trump has gone from an embarrassment to a cause for serious alarm" among Republican leadership.

Trump has come under fire for his recent comments about Mexican immigrants, which cost him some business partnerships like the PGA and Macy's.