Top House Republican hasn't seen 'evidence' of Trump-Russia contacts

— -- The chairman on the House Intelligence Committee said Monday that he had not seen any "evidence" of contacts between the Trump campaign and Russian government amid an investigation into Russian activities during the 2016 election.

"We still have not seen any evidence of anyone ... from the Trump campaign or any other campaign for that matter that's communicated with the Russian government," Rep. Devin Nunes, R-Calif., told reporters at the Capitol.

“That doesn't mean they don't exist but I don't have that. And what I've been told is, by many -- by many folks, is that there's nothing there,” he added.

Authorities were looking into communications between Trump associates and suspected Russian intelligence officials ahead of the election, sources told ABC News.

At a separate press conference, Rep. Adam Schiff, D-Calif., the top Democrat on the House Intelligence Committee, said that it’s premature to draw any conclusions on the alleged communications.

“We haven't reached a conclusion, nor should we, on issues of collusion because we haven't interviewed a single witness or reviewed a single document,” Schiff told reporters.

Schiff said it was “completely inappropriate” for the White House to ask CIA officials and Republican members to knock down the report from The New York Times and that anyone receiving that request “should politely decline.”

The New York Times recently reported that Trump associates inside and outside the presidential campaign had repeated contact with Russian intelligence officials before the election, but Trump has repeatedly derided the story as "fake news." ABC News sources have also disputed elements of the story, but would not offer any further details or explanation, citing the sensitive nature of the matter.

One of the associates, former Trump campaign manager Paul Manafort, called the allegations "ridiculous."

Investigations are ongoing in the House and Senate intelligence committees as well as the FBI.

Nunes, who said he was conveying what he was learning from the intelligence community, said his committee is in the early stages of its work. They have set the parameters of the investigation, and are in the process of requesting materials to receive and review.

Schiff told reporters he would prefer the investigation to be conducted by an independent commission or even a joint effort between the Senate and House Intelligence committees, due to a lack of resources and staff.

A Trump ally who advised the transition, Nunes pushed back strongly on the suggestion that talking to a reporter at the request of the White House compromised his committee's investigation.

He said he was given a phone number to call but no directions on what to say to the reporter.

“How is it compromised if I'm trying to be transparent with the press?” he said, pointing out that he spoke frequently with reporters on Capitol Hill about the story.

Nunes dismissed the idea of requesting Trump’s tax returns, and did not say if he would support the appointment of a special prosecutor to investigate any alleged contacts. He also punted on the question of whether Attorney General Jeff Sessions should recuse himself from any investigations of the administration on the matter, despite his own close work with the Trump campaign.

“If...we have serious crimes have been committed, it would be something that we would consider,” Nunes said. “At this point, we don't have that. The only serious crimes we have are leaks that have come out of our government.”

Nunes said he was wary of leading a "witch hunt" against American citizens mentioned in press reports about alleged contacts between the Trump campaign and Russia.

"We can't have McCarthyism back in this place," he said of the congressional investigation.

The California Republican also defended the former national security adviser's conversations with the Russian ambassador -- claiming that Mike Flynn was doing his job by discussing "petty" actions of the Obama administration in response to Russian election interference, which he did not think constituted official sanctions. He also called concerns that Flynn may have violated the Logan Act "ridiculous."

The 1799 law, which bars individuals from communicating with foreign governments, has never been used.

Flynn was asked to resign from his White House post after misrepresenting his communications with the Russian ambassador to Vice President Mike Pence and other administration officials.

ABC's Mike Levine contributed to this report.