The news of a dozen more Russian indictments in special counsel Robert Mueller's investigation has prompted Senate Minority Leader Chuck Schumer to urge President Trump to nix his upcoming meeting with Vladimir Putin, who has proven himself to be an "adversary." Teach him a lesson that Russia can not interfere in our elections, Schumer wrote in a statement.

Dem. Senate leader Chuck Schumer asks #Trump to Cancel Putin meeting on Mon. after indictments pic.twitter.com/IZibupX6BJ — Joyce Karam (@Joyce_Karam) July 13, 2018

House Minority Leader Nancy Pelosi added that if Trump does proceed with the meeting, he should at least demand Russia cease the interference. Anything less would be a "betrayal" of American democracy.

Pelosi: The stakes for the upcoming Trump-Putin mtg could not be higher...Trump must demand..s real..agreement that the Russians will cease their ongoing attacks on our democracy. Failure to stand up to Putin would constitute a..betrayal of the Constitution and our democracy. — Chad Pergram (@ChadPergram) July 13, 2018

Sen. Mark Warner (D-VA) added his voice to the mix, telling reporters that Trump's meeting with Putin should not be one-on-one. Because of the president’s ad hoc style, he's afraid the president "could be taken advantage of."

Republicans, too, are insisting Putin is no friend of the U.S.

The U.S. intelligence community knows that the Russian government attacked the U.S. This is not a Republican or a Democrat view -- it is simply the reality. All patriotic Americans should understand that Putin is not America's friend, and he is not the President's buddy... pic.twitter.com/GfgtDKKtSF — Senator Ben Sasse (@SenSasse) July 13, 2018

Trump is in Europe this week for the NATO summit. Ahead of the trip, Trump predicted his meeting with Putin would be his "easiest" stop on his European tour. Yet, pushing back against reports he's too soft on Russia, Trump said during his press conference with British Prime Minister Theresa May Friday that his policies have put Russia in its place.