Sen. Chuck Schumer (D-N.Y.) on Monday stepped up his criticism of House Intelligence Chairman Devin Nunes, calling on House Speaker Paul Ryan to replace him. 
"Without further ado, Speaker Ryan should replace Chairman Nunes," the Senate minority leader said from the floor. "If Speaker Ryan wants the House to have a credible investigation, he needs to replace Chairman Nunes."
Nunes caused an uproar last week when he told the press that he had seen intelligence showing that members of President Trump's transition team had been caught up in surveillance operations — without first discussing the information with fellow committee members. He later briefed Trump on the information. 
On Monday, Nunes confirmed that he was on White House grounds the day before the announcement, further raising speculation that the information he saw originated from within the administration. 
Schumer argued on Monday that Nunes is acting like someone who wants to protect Trump even though his committee is investigating Russia's meddling in the White House race, including any potential ties between the campaign and Moscow. 
"Chairman Nunes is falling down on the job and seems to be more interested in protecting the president than in seeking the truth. You cannot have the person in charge of an impartial investigation be partial to one side. It's an inherent contradiction," Schumer added. 
Nunes said that he was on the White House grounds, but not in the White House itself, for meetings "to confirm what I already knew." He said no one in the White House knew he was there.
Schumer's comments on Monday afternoon are a marked shift from late last week, when he raised the idea of Nunes being ousted from the committee in less forceful terms.
"I hope ... he either comes to his senses or maybe Speaker Ryan replaces him," Schumer said of the GOP chairman on CNN's "Situation Room."
Democrats don't have the ability to make Nunes step down, and Ryan has given no public hint that he's considering asking him to hand over his gavel. 
But Democrats slammed Nunes for briefing Trump without first speaking to their panel. Democrats on the committee say they still have not seen intelligence to back up Nunes's claims.
Nunes has defended his decision to not share his information with Democrats, saying he is protecting his source and separately saying that he had a "duty and an obligation" to brief Trump.