 -- House Speaker Paul Ryan has rebuked his primary opponent for suggesting that it might be worth exploring the possibility of deporting all Muslims.

Ryan called the comments "dark" and "indefensible" in a Wisconsin radio interview Friday morning.

"I hate to even give such comments currency by even talking about them," Ryan told Wisconsin WTMJ radio host Charlie Sykes. "This is not conservatism, this is not the U.S. Constitution, this is not the Bill of Rights, let’s just be really clear about this."

He continued: "That kind of dark, grim, indefensible thinking comments is going to be thoroughly rejected and repudiated on Tuesday I think."

Republican businessman Paul Nehlen, who is challenging the speaker in a primary election, suggested that there should be a “discussion” on the possibility of deporting all Muslims from the United States.

"The question is, why do we have Muslims in the country?" Nehlen said in a Monday radio interview with Chicago's AM 560 "The Answer."

Although Ryan is widely expected to win Tuesday's primary, Nehlen’s campaign enjoyed a bounce in publicity this week when Donald Trump all but declared political war on the Republican Party establishment by withholding an endorsement of Ryan and complimenting Nehlen for running a "very good campaign."

The political standoff between the party’s nominee and the party’s highest ranking elected official showed no signs of easing, with Ryan opting to skip a scheduled Trump campaign event on his home turf Friday night.

While Trump has yet to weigh in on Nehlen’s comments about Muslim deportation, Ryan reiterated Friday that his endorsement of the party’s nominee is not a "blank check" and said "of course" there's a point at which he would consider revoking his endorsement.