Four powerful U.S. senators — two on each side of the aisle — on Sunday called for Republicans and Democrats to join forces to probe and fight Russian interference in the U.S. political process.

The "stakes are too high" for the issue to become partisan, the group of senior lawmakers wrote.

"For years, foreign adversaries have directed cyberattacks at America’s physical, economic, and military infrastructure, while stealing our intellectual property," Senators John McCain, R-Ariz., Lindsey Graham, R-S.C., Charles Schumer, D-N.Y., and Jack Reed, D-R.I., said in the statement released Sunday.

"Now our democratic institutions have been targeted. Recent reports of Russian interference in our election should alarm every American," they added.

In a press conference later on Sunday, Schumer said that the issue is too serious to point fingers at any individual.

"The outrage is not directed at any individual but at foreign government," he said. "This gets to the wellspring of our democracy."

The CIA has concluded that Russia mounted a covert intelligence operation to influence the U.S. election in an effort to help Donald Trump win, a congressional official knowledgeable on the matter told NBC News on Saturday.

The CIA says Russia was behind hacks of Democratic email accounts and other efforts that appeared to harm Hillary Clinton's candidacy.

Although the president-elect has repeatedly said he does not accept the findings of the spy agencies he will soon lead, Schumer said he believes that the Trump administration would get behind an investigation. This also despite the fact that incoming Chief of Staff Reince Preibus on Sunday morning dithered when asked about the subject.

Any investigation would have to wait until Congress's next session begins in early January, as the current legislature has adjourned.

Schumer said the investigation is not just limited to the election, but will also examine whether foreign governments have been stealing American intellectual property.

"What the four of us intend this investigation to look at is foreign governments hacking into American institutions, government and otherwise," he said.

The four senators warned that “Congress’ national security committees have worked diligently to address the complex challenge of cybersecurity, but recent events show that more must be done."

"Democrats and Republicans must work together," they said, adding: "This cannot become a partisan issue. The stakes are too high for our country."