On Capitol Hill, both Democrats and Republicans demand Mueller report be made public

The demands for complete transparency on Friday came quickly -- from Democrats and Republicans alike.

Almost immediately after news broke that special counsel Robert Mueller's report had been handed over to Attorney General William Barr, members of Congress called for the whole report to be made public.

"Now that Special Counsel Mueller has submitted his report to the Attorney General, it is imperative for Mr. Barr to make the full report public and provide its underlying documentation and findings to Congress. Attorney General Barr must not give President Trump, his lawyers or his staff any ‘sneak preview’ of Special Counsel Mueller's findings or evidence, and the White House must not be allowed to interfere in decisions about what parts of those findings or evidence are made public," said House Speaker Nancy Pelosi and Senate Minority Leader Chuck Schumer in a statement.

They threatened to sue the Trump administration to get Mueller's complete report and any related evidence if the Justice Department refuses to turn it over to Congress.

Attorney General William Barr has said that after he reviews the report, he'll advise the chairmen and ranking members of relevant congressional committees about details that can be released "consistent with the law." He will do so "as soon as this weekend," Barr wrote in a letter to Congress.

Pelosi will hold a Democratic conference call Saturday afternoon with House committee chairs to go over strategy for dealing with Mueller's findings and Barr's upcoming report as their investigations ramp up.

Key questions now: How much will Barr share? And will Congress be able to secure the full Mueller report in order to make it public?

Pressure from Democrats and from some Republicans for full transparency was clear Friday, while other Republicans echoed Barr's careful wording at his confirmation hearing that he would try to make as much of the report public as possible under the law and Justice Department rules.

According to federal regulations, the special counsel's final report should be "a confidential report explaining the prosecution or declination decisions reached by the Special Counsel."

In a statement, Senate Majority Leader Mitch McConnell said: "I hope the Special Counsel’s report will help inform and improve our efforts to protect our democracy.

"The Attorney General has said he intends to provide as much information as possible. 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."

Democratic leader Rep. Hakeem Jeffries sent out a blunt tweet: #MuellerTime: "Every. Single. Word."

"Full transparency. No waiting. Attorney General Barr must immediately provide Congress and the public with Mueller’s entire report and supporting material, not just his summary findings. The American people have a right to know everything," said Democratic Sen. Chris Van Hollen of Maryland.

Rep. Jerry Nadler, the Democrat who chairs the House Judiciary Committee and one member expected to see Barr's report this weekend, said he looks forward "to getting the full Mueller report and related materials."

"Transparency and the public interest demand nothing less," he said.

Rep. Doug Collins, the top Republican on the House Judiciary Committee, also called for the entire report to be made public.

"I fully expect the Justice Department to release the special counsel’s report to this committee and to the public without delay and to the maximum extent permitted by law," Collins said in a statement.

Sen. Lindsey Graham, R-S.C., the chairman of the Senate Judiciary Committee, blocked a measure in the Senate last week that would have encouraged the Justice Department to make the full report public. A resolution in the House calling for the same passed 420-0.

"I will work with Ranking Member Feinstein and our House Judiciary Committee colleagues to ensure as much transparency as possible, consistent with the law," Graham said on Twitter Friday evening.

Other Republicans defended Trump, echoing his criticisms of the investigation into ties between his 2016 presidential campaign and the Russians as a witch hunt.

"The only collusion was between Democrats and many in the media who peddled this lie because they continue to refuse to accept the results of the 2016 election. #WitchHunt." said Rep. Steve Scalise, the House Republican Whip from Louisiana.

ABC News' John Parkinson, Benjamin Siegel, Mariam Khan and Trish Turner contributed to this report.