Senate Majority Leader Mitch McConnell on Monday blocked a resolution calling for the public release of the special counsel Robert Mueller's full report on his investigation into Russia's interference in the 2016 election and whether President Donald Trump obstructed justice.

A summary released by Attorney General William Barr says the investigation found no evidence that Trump's campaign colluded with Russia but does not exonerate the president.

Some lawmakers want the report to be made public, saying it could show wrongdoing by Trump, reveal details of Russia's operation, and aid other investigations related to Trump.

McConnell said before the summary was released that he wanted "as much openness and transparency as possible" about the report.

McConnell cited national security and said more time was needed to review the report. Sen. Chuck Schumer, the minority leader, said he was "befuddled" by McConnell's reasoning, as the resolution did not call for the report to be released immediately.

Senate Majority Leader Mitch McConnell on Monday blocked a resolution calling for the special counsel Robert Mueller's full report on his Russia investigation to be released publicly, three days after saying he wanted "as much openness and transparency as possible" about the report.

McConnell cited national security when blocked the nonbinding resolution, which the House had passed unanimously. He also said Attorney General William Barr needed time to determine what could be released publicly.

"To date, the attorney general has followed through on his commitments to the Congress," McConnell said. "One of those commitments is that he intends to release as much information as possible."

Read more: Barr's summary of the Mueller report is out. Here are the key Trump-Russia questions we still don't have answers to.

Senate Minority Leader Chuck Schumer, who put forward Monday's resolution, said it did not call for the report to be released immediately.

"I'm sort of befuddled by the majority leader's reasoning in this regard because it is not in the words of this resolution," Schumer said, according to The Hill.

President Donald Trump. AP Photo/Alex Brandon

On Friday, Mueller gave Barr his report on his investigation into Russia's interference in the 2016 election and whether President Donald Trump obstructed justice. On Sunday, Barr sent Congress a four-page summary of Mueller's report.

According to Barr's summary, the report said that the investigation found neither Trump nor his campaign conspired or colluded with Russia but that it did not exonerate him.

McConnell said in a statement posted on Twitter on Friday that he appreciated Barr's intention to "provide as much information as possible" about the report.

"As I have said previously, I sincerely hope he will do so as soon as he can, and with as much openness and transparency as possible," he said.

McConnell and Trump. Mark Wilson/Getty Images

Democrats have accused Barr of bias in reaching his conclusions. John Dean, who was President Richard Nixon's lawyer during the Watergate scandal, said on Monday that Barr may be hiding something "fairly ugly" from the report.

Read more: Pelosi and Schumer charge that Attorney General William Barr is 'not in a position to make objective determinations' about the Mueller report

Trump has described Barr's summary as vindicating him and is using it to fundraise for his 2020 reelection campaign.

But lawmakers who are calling for the full report to be made public have argued that doing so will provide a full picture of Russia's interference and any potential wrongdoing by Trump, his associates, or Russian operatives.

Schumer called for bipartisan transparency on the Senate floor on Monday.

"Whether or not you're a supporter of President Trump ... there is no good reason not to make the report public," he said, adding, "It's a simple request for transparency — nothing more, nothing less."

Attorney General William Barr. AP Photo/Kevin Wolf

A former senior Justice Department official who previously worked closely with Mueller told Business Insider that while the investigation "may not have found evidence that rose to the level of criminal conduct," it "doesn't mean they didn't find evidence of wrongdoing."

"If — or when — Congress and the public get that information, it will undoubtedly create another firestorm for the president," the former official said.

Read more: Democratic presidential candidates are leading calls for the Mueller report to be made public

Democrats have also called for the evidence from Mueller's inquiry to be released for their own investigations — some of the many related to Trump and his administration still underway.

Trump told reporters on Monday that the release of the full report is "up to the attorney general, but it wouldn't bother me at all."