An extraordinary scene unfolded on the Senate floor Friday as Republican Sen. Ted Cruz bluntly accused Majority Leader Mitch McConnell of lying and said he's running the Senate like his Democratic predecessor. 

The charges from the Texas senator and GOP presidential candidate were a rare departure from the Senate's usual staid decorum, even for a politician famous for his fiery speeches. 

At issue were assurances Cruz claimed McConnell, R-Ky., had given that there was no deal to allow a vote to renew the federal Export-Import Bank -- a little-known federal agency that has become a rallying cry for conservatives. Cruz rose to deliver his remarks moments after McConnell had lined up a vote on the bank. 

"It saddens me to say this. I sat in my office, I told my staff the majority leader looked me in the eye and looked 54 Republicans in the eye. I cannot believe he would tell a flat-out lie, and I voted based on those assurances that he made to each and every one of us," Cruz said. 

"What we just saw today was an absolute demonstration that not only what he told every Republican senator, but what he told the press over and over and over again, was a simple lie." 

Reports had emerged earlier this year that McConnell privately pledged a vote on the Ex-Im Bank, in exchange for winning support on President Obama's trade agenda. Cruz says he was assured at the time there was no deal. 

He also charged that the Senate under Republican control is no different from when Harry Reid of Nevada ran the chamber and was accused by the GOP of shutting down debate and limiting amendments. 

"Now the Republican leader is behaving like the senior senator from Nevada," Cruz complained. He also derided an announcement from McConnell that the Senate will vote Sunday to repeal Obama's health care law, calling it "an empty show vote" and "exercise in meaningless political theater" because the legislation will inevitably fail to get the 60 votes needed to advance. 

"We keep winning elections and then we keep getting leaders who don't do anything they promised," Cruz said. 

The majority leader was not on the Senate floor when Cruz issued his attack, and ignored reporters who tried to ask him about it in the Capitol's hallways. A spokesman said McConnell would have no response. 

McConnell and Cruz have never had a thriving relationship. The new majority leader's allies earlier this year derided Cruz's Senate record, complaining that he often speaks out but has skipped important developments. 

Some close to McConnell call Cruz, "Mr. 1 percent," referring to his share of support in the crowded race for the GOP presidential nomination. Recent polls have him a few points higher among more than a dozen contenders. 

Cruz has grown increasingly outspoken about his contempt for McConnell and other Republicans, using his newly published book, "A Time for Truth," to attack his colleagues on various fronts and accuse them of failing to stand up for their principles. 

It is rare for a senator to launch such a heated attack on the floor. Senate rules say, "No Senator in debate shall, directly or indirectly, by any form of words impute to another Senator or to other Senators any conduct or motive unworthy or unbecoming a Senator." 

Fox News' Chad Pergram and The Associated Press contributed to this report.