Top Democrats called Friday for President Donald Trump to cancel his planned summit next week with Russian President Vladimir Putin following the announcement by the Justice Department that 12 Russian intelligence officers had been indicted over the hacking of the Democratic National Committee and Hillary Clinton’s campaign during the 2016 presidential race.

But as the list of Democrats demanding the cancellation mounted Friday afternoon, a senior administration official told NBC News there was a "zero" percent chance that the meeting would be scratched. Later, White House Press Secretary Sarah Sanders said the summit was "still on."

“President Trump should cancel his meeting with Vladimir Putin until Russia takes demonstrable and transparent steps to prove that they won’t interfere in future elections,” Senate Minority Leader Chuck Schumer said in a statement shortly after the announcement. “Glad-handing with Vladimir Putin on the heels of these indictments would be an insult to our democracy.”

House Minority Leader Nancy Pelosi, D-Calif., who said early Friday afternoon the president should use the meeting to "demand and secure a real, concrete and comprehensive agreement that the Russians will cease their ongoing attacks on our democracy," later called for its cancellation.

“President Trump’s continued refusal to condemn the Russians’ attacks on our democracy, even after Special Counsel Mueller indicted 12 Russian intelligence officials for interfering in the 2016 election, makes it clear that meeting with Putin would be both pointless and dangerous. The Trump-Putin meeting must be canceled," she said in a later statement.

Sen. Jack Reed of Rhode Island, the top Democrat on the Senate Armed Services Committee, also called on Trump to immediately cancel the summit, "in light of this stunning indictment by the Justice Department that these Russian conspirators attacked our democracy and were communicating with Americans to interfere in our election."

So did Rep. Adam Schiff, D-Calif., ranking member on the House Intelligence Committee. "Because it is abundantly clear that the President will not confront Putin on the charges laid out in this indictment and its predecessor, and in the wake of his disastrous visit with our allies, it is in the strong national security interests of the United States for the President to cancel any meeting with Putin," he said in a statement.

Sen. Cory Booker, D.J. tweeted that the president "should cancel Monday's summit with Putin. If he doesn't and fails to confront Putin it's Presidential malpractice."

Some Democrats, such as Sen. Mark Warner of Virginia, the ranking Democrat on the Senate Intelligence Committee — which has been conducting its own probe into Russian meddling — and Rep. Dina Titus, D-Nev., said Friday that there should be no one-on-one meeting between Trump and Putin.

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Other Democrats, such as Sen. Bob Menendez, D-N.J., said Trump should still meet with Putin to deliver demands to the Russian leader that he turn over individuals named in the indictment, withdraw from Crimea and pressure Iran to leave Syria.

Friday's news came just days ahead of the planned Putin summit, as Trump met Friday with Queen Elizabeth II in England.

Congressional Democrats applauded the announcement, including some directly affected by the 2016 presidential campaign.

Rep. Debbie Wasserman Schultz, D-Fla., who was DNC chairwoman during the cyberattacks, noted Friday that the committee was the first major target of the Russian attack on the U.S. She resigned as DNC chairwoman in July 2016 after emails surfaced showing committee officials favored Clinton over Sen. Bernie Sanders, I-Vt.

“I strongly believe that every individual who helped carry it out — foreign or domestic — should be held accountable to the fullest extent of the law,” Wasserman Schultz said in a statement. “I’m pleased that the Justice Department is following the facts wherever they may lead, despite Donald Trump’s dangerous distortions and his refusal to acknowledge the conclusions reached by the American intelligence community.”

Sen. Tim Kaine, D-Va., Clinton’s vice-presidential nominee, tweeted Friday that the indictments "prove, yet again, that hostile Russian actors targeted Americans with sophisticated crimes in 2016. This investigation must continue — unobstructed — to keep protecting Americans, safeguarding future elections, and holding criminals responsible for their actions.”

The top Democrat on the House Judiciary Committee, Rep. Jerry Nadler of New York, said Friday “this is not a joke” and “this is no witch hunt."

“It is now obvious that any Republican still standing in the way of the special counsel’s investigation not only abets the obstruction of justice, but gives comfort to a foreign adversary,” he said.

Few Republicans — and no members of GOP leadership or committee chairs conducting Russia investigations — immediately weighed in on the indictment. AshLee Strong, a spokeswoman for Speaker Paul Ryan, later released a short statement to NBC News reacting to the indictment: “We’ve said all along we know Russia meddled in our elections and we’re glad these hackers are being held to account.”

She did not respond to a request for comment about the unnamed congressman unnamed congressional candidate who the indictment said had reached out to hacker Guccifer 2.0.

One GOP member, Rep. Carlos Curbelo of Florida, called on the Department of Justice to release the name of that candidate. "I support Dir. Mueller's investigation & efforts to hold accountable all the individuals & entities who may have acted to undermine or manipulate our elections," he tweeted. Rep. Chris Stewart, R-Utah, a member of the House Intelligence Committee, said he had "always supported the Special Counsel and the investigation should continue unimpeded."

Rep. Lee Zeldin, R-N.Y., applauded the news while reflecting Republican calls for limits on the probe's scope: “Great progress today by DOJ/FBI & our Intel community to bring transparency & accountability re DNC/DCCC hacking," he tweeted. "Regardless of being GOP or Dem, conservative or liberal, Americans must stand united against meddling by foreign adversaries. Keep investigation w/in scope!”

Later, Rep. Mark Meadows, chairman of the House Freedom Caucus, sounded a similar note. "If at any time you can put bad guys in jail, that is a good thing," he told reporters. "And so obviously we applaud the work of the special counsel — hopefully that brings us closer to a conclusion."

He also denied reports he was in the process of filing a bill to impeach acting attorney general Rod Rosenstein, saying only that the move had been "an option on the table for months."

Few Republicans who reacted to the news mentioned the president or the upcoming summit with Putin. Rep. Walter Jones, R-N.C., said that the sitdown offered Trump "the opportunity to confront Putin on this matter, and he should take it."

Retiring Sen. Jeff Flake, R-Ariz., a frequent Trump critic, addressed the president directly. "Mr. President, as today’s indictments reaffirm, election interference is not a question to be asked of Vladimir Putin, but a statement to be made to Vladimir Putin: You interfered in our elections."

Sen. John McCain, R-Ariz., appeared to be the first Republican to suggest the meeting between the two leaders should now be called into question, saying in a statement that Trump "must be willing to confront Putin from a position of strength and demonstrate that there will be a serious price to pay for his ongoing aggression towards the United States and around the world. If President Trump is not prepared to hold Putin accountable, the summit in Helsinki should not move forward."

The Senate left Washington for the week on Thursday afternoon, and House lawmakers left for the week on Friday morning before the release of the indictment.

Meanwhile, Sen. Ron Wyden, D-Ore., said that the major voting machine companies are refusing to answer “the most basic questions about whether they are adequately protecting our elections.” He said that Congress should now pass his proposed legislation that would require paper ballots and audits.

“Anything less is an invitation to Russian to do this again,” Wyden tweeted.