WASHINGTON Democrats vowed Wednesday to pursue a two-path track to probe the ties between President Donald Trumps administration, his campaign and the Russian government, calling revelations about extensive interactions chilling.

Ive been in Congress a long time. Ive never seen anything like this, said Senate Minority Leader Chuck Schumer (D-N.Y.), referring to the resignation of National Security Advisor Michael Flynn , apparent Trump administration lies, and fresh reports that there were constant contacts between the Trump campaign and Russian intelligence services.

Nothing less than our system of checks and balances, democratic institutions, the rule of law and our national security is at stake, Schumer said.

Schumer said the first track for Congress is to pursue committee investigations, led by the Intelligence Committee, with additional oversight from panels such as the Judiciary Committee when the Department of Justice is at issue.

Second, he renewed his call for an independent probe by federal law enforcement an investigation he said must exclude new Attorney General Jeff Sessions , who was a fixture on Trumps campaign, along with Flynn.

As a key step in that direction, Schumer said that Trump administration and campaign officials must preserve all of their email conversations and other documents.

Schumer made his remarks while flanked by the top Democrats on the Senate Intelligence, Judiciary and Foreign Relations committees in a show of party unity.

Sen. Dianne Feinstein (D-Calif.) told HuffPost her Judiciary Committee Democrats were drafting a letter to Sessions seeking a formal commitment that he will recuse himself.

If this trail leads to the Oval Office, the person investigating that trail should not be the same person who helped put President Trump there. End of story, Schumer said.

Feinstein and Sen. Mark Warner (D-Va.), the ranking Democrat on the Intelligence Committee both told reporters later that the stakes are as high as Schumer said.

Feinstein reminded reporters that the intelligence community has already released a public report that says Russia actively intervened in the 2016 presidential campaign for the benefit of Trump.

Thats there for the record, and thats there for the public to look at. And that is startling, Feinstein said. When you begin to learn there were people in contact from the campaign or associates of the president during that period, it takes on a whole other point of view.

Warner pointed out that the bigger picture includes concerted and successful hacking attempts, a massive Russian disinformation and fake news operation, and the many selective leaks targeted at Hillary Clinton. The scope is even expanded [now to] any contacts between members of either campaign and Russian officials before the election, and obviously part of this in terms of whats happened with Gen. Flynn, now extends into contacts that took place after the election, Warner said.

Republicans have not denigrated the seriousness of the charges against Trump and his team, but are counseling a restrained response.

Im no more worried about it than I was when the Obama report came out, said Sen. Roy Blunt (R-Mo.), a member of the Intelligence Committee, referring to the same intelligence community assessment that Feinstein raised. Well just see. I think its better to not reach conclusions too quickly here, and to look at everything and we havent had a chance to do that yet.

Blunt and Sen. John Cornyn (R-Texas) both said it was much too early to be talking about independent investigators and recusals of Sessions. I think thats ridiculous, Cornyn told reporters.