Undeterred by President Donald Trump's claim of "complete and total exoneration" from a summary of the special counsel's report on Russian interference, Democrats on Sunday vowed to press ahead with their multiple investigations into the president and whether he obstructed justice.

Rep. Jerrold Nadler, D-N.Y., whose panel has jurisdiction over impeachment, pledged to pick up where investigators left off and, if necessary, subpoena Attorney General William Barr to testify. In an impromptu news conference in New York City, he seized on special counsel Robert Mueller's refusal to exonerate Trump on the question of obstruction of justice, suggesting that Barr's summary was "a hasty, partisan interpretation of the facts."

"President Trump is wrong. This report does not amount to a so-called total exoneration," Nadler said. "It is unconscionable that President Trump would try to spin the special counsel's findings as if his conduct was remotely acceptable."

Mueller on Friday submitted a confidential report to Barr, who reviewed the document and sent congressional leaders a four-page summary of Mueller's "principal conclusions" late Sunday afternoon. Democrats argued that the summary was insufficient - and a work product from a Republican attorney general appointed by Trump.

They insisted that Congress and the American people need to see the full report from Mueller and the underlying documents so they could reach their own conclusions.

In a joint statement, House Speaker Nancy Pelosi, D-Calif., and Senate Minority Leader Chuck Schumer, D-N.Y., said Barr's letter "raises as many questions as it answers."

"The fact that Special Counsel Mueller's report does not exonerate the president on a charge as serious as obstruction of justice demonstrates how urgent it is that the full report and underlying documentation be made public without any further delay," they said. "Given Mr. Barr's public record of bias against the Special Counsel's inquiry, he is not a neutral observer and is not in a position to make objective determinations about the report."

House Democrats have faced resistance from the White House to their repeated requests for documents, and the Barr summary and Trump's response increase the likelihood of an escalating standoff between Congress and the executive branch over material and witnesses.

In a joint statement Sunday night, Nadler, House Intelligence Committee Chairman Adam Schiff, D-Calif., and House Oversight Committee Chairman Elijah Cummings, D-Md., called for Barr to appear before the Judiciary panel "without delay" and for the Justice Department to release the full Mueller report and all of the underlying documents.

"The Special Counsel's Report should be allowed to speak for itself, and Congress must have the opportunity to evaluate the underlying evidence," the chairmen said in their statement. "These shortcomings in today's letter are the very reason our nation has a system of separation of powers."

In addition to seeking testimony from Barr, Democrats on the House Judiciary Committee discussed pursuing Mueller to appear before Congress, especially if the panel is unsuccessful in obtaining the special counsel's full report. The committee's Democrats, scattered around the country, held an emergency conference call Sunday evening to discuss the summary and the next steps, according to a participant who spoke on condition of anonymity to freely describe the conversations.

Even before Barr sent his summary to Capitol Hill, six House committee chairmen had told their Democratic colleagues on Saturday that they would pursue their investigations into Trump's businesses, the role banks played in funding the Trump organization and whether the president abused the powers of his office no matter what Mueller concluded.

In the summary, Barr said Mueller also found no conspiracy between the 2016 Trump campaign and Russia, a conclusion that took what little wind was left in the sails of Democrats calling for impeachment.

In an interview with The Washington Post this month, Pelosi spelled out a critical precondition for moving toward impeachment proceedings: support from Republicans so that it would be considered a bipartisan movement against Trump, similar to the last days of Richard Nixon's presidency in 1974.

Pelosi said impeachment would be "so divisive to the country that unless there's something so compelling and overwhelming and bipartisan, I don't think we should go down that path."

"He's just not worth it," she said of Trump.

Now, after Sunday's findings, Republicans rallied around Trump and signaled that it would take dramatic new discoveries to ever get them to break from the president.

Democrats will face intense pressure from jubilant Republicans, who welcomed Barr's summary and insisted it had cleared the president. House Minority Whip Steve Scalise, R-La., said the report vindicates Trump, and House Minority Leader Kevin McCarthy, R-Calif., declared Sunday that "it is time we move on for the good of the nation."

Sen. Christopher Coons, D-Del., a member of the Senate Judiciary Committee, predicted Sunday that "we will have a hard fight ahead over release of the full report and materials" but insisted that Democrats are "justified in seeking a broad view of what materials led to [Mueller's] conclusion."

In the House, Judiciary Committee member Rep. Jamie Raskin, D-Md., voiced the similar conviction that "now more than ever, we need to see the Mueller report and all of the underlying evidence."

He added that Barr's "analysis and rationale are fair game for congressional investigation too," pointing out that it was Barr's conclusion, not Mueller's, that Trump had no ill intent behind the evidence that could be considered obstruction of justice.

As for the Mueller report's apparent confidence that Trump and his subordinates had not conspired with Russians to sway the 2016 election, even when presented with the opportunity, Raskin insisted that he had "regarded the question of so-called collusion as an irrelevant distraction from the very beginning."

"There is no crime known as collusion except in the field of antitrust law," he said.

But that doesn't mean Democrats are likely to drop the Russia-focused probe of their Trump investigations.

"The job of the special counsel is very different than our job; they're looking for specific statutory offenses and a quantum of evidence that surpasses beyond a reasonable doubt," Raskin said. " That's very different than what we're looking for in terms of examining threats to the political sovereignty of the United States."

Some Democrats responded to Sunday's news by immediately questioning Barr's motives, noting that he was appointed by Trump. Sen. Chris Murphy, D-Conn., took to Twitter to write that "maybe Barr's interpretation is right. Maybe it's not. But why the heck would we be ok with an ally of President, appointed because of his hostility to the Mueller investigation, tell us what the report says?"

"Give Congress the report," he wrote. "Give the public the report. Now."

Sen. Richard Blumenthal, D-Conn., a member of the Senate Judiciary Committee, also pressed for greater transparency, saying in a tweet that on the issue of obstruction of justice, Mueller "tossed a jump ball, & the AG tipped it to President Trump, but shared none of the information supporting his conclusion."