Supporters of the Vermont senator confronted Reid at a delegate meeting Thursday.
The leak has roiled the party amid its national convention in Philadelphia.
The Arizona Republican said Trump had a "good response" to "lock her up" chants.
Sen. Jack Reed called Trump "combustible [and] impulsive."
McConnell said he needs a "well crafted, highly effective speech."
McConnell said Trump's comments were "not accurate."
Sen. Ron Johnson said he would vote for the GOP nominee.
A handful of candidates, including Wisconsin's Russ Feingold, won't be in Philadelphia.
The two senators called the strategy a "dangerous scheme."
Lawmakers are offering dueling sanctions bills.