Republicans were taken aback when 2016 presidential hopeful Sen. Ted Cruz (R-Texas) attack the leader of his own party on the floor of the Senate, a remarkable breach of protocol.

Cruz accused Senate Majority Leader Mitch McConnnell (R-Ky.) of lying to him and argued that he was not trustworthy, according to a Guardian report.

Cruz is considered an outside contender for the 2016 GOP nomination, and this latest move may be an attempt to boost his profile and prove that he is not afraid to stand up to even the leaders of his own party.

In a speech on the Senate floor, Cruz said McConnell had assured him that there would be no deal to allow a vote on renewing the federal Export-Import bank, a federal agency that conservatives have wanted to shut down. McConnell had just lined up a vote on the Export-Import Bank when Cruz made the remarks.

Cruz said that it “saddens me” to point out McConnell’s deception, saying that he lied not only to him but to the other Republicans in the Senate. He said he “cannot believe he would tell a flat-out lie.”

He said that McConnell told a “simple lie” to the Senators as well as to the press.

McConnell wasn’t on the Senate floor at the time. He would not answer questions from reporters while in the hallways of the Capitol, and a spokesman indicated there would be no response.

Cruz has become more and more outspoken about his feelings for McConnell and the rest of the Republican Party. Cruz is considered to be one of the foremost faces of the so-called “Tea Party” faction of the Republican Party, which has a more libertarian, anti-government bent and is less willing to compromise — something that has irritated the rank and file of the Republican Party, including McConnell.