Senators express concern over Trump campaign's contact with Russia

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WATCH Questions about ex-national security adviser Michael Flynn continue to swirl in Washington

Senators from both sides of the aisle are expressing concern over reports that Donald Trump's campaign had contact with potential Russian operatives -- arguing this is further proof why thorough investigations are necessary.

"More and more questions are coming out about this and it’s disturbing. It’s highly disturbing," said Sen. Cory Booker, D-N.J. "Congress has a sworn obligation to get to the bottom of this and everything right now to me just further illustrates the urgency for investigating this thoroughly and exhaustively."

"It just calls out for the most thorough and deepest investigation that can be had," said Sen. Bob Menendez, D-N.J.

"This issue has to be pursued and we have to follow it to its conclusion and do whatever is necessary to achieve that," said Republican Sen. John McCain, who has been critical of the Trump administration.

White House press secretary Sean Spicer was asked by ABC News' Jonathan Karl during Tuesday's press briefing if Trump's campaign, including former national security adviser Lt. Gen. Mike Flynn, had any contact with Russia.

"I don’t have any -- there’s nothing that would conclude me that anything different has changed with respect to that time period," Spicer said.

Earlier this week, Sen. Rand Paul, R-Ky., suggested that investigations into Flynn's resignation would be "excessive." Flynn resigned from his position as national security adviser Monday night. When told about that comment from Sen. Paul, McCain smirked.

"Really? That's interesting," McCain said, smiling. "The fact is this is a very serious issue and I think most Americans appreciate that."

Virginia Sen. Tim Kaine, who was on the 2016 Democratic ticket, said he was not surprised by the reports -- especially after the intelligence community's January assessment that the Russian government had helped orchestrate cyber-attacks against the Democratic National Committee and Hillary Clinton's campaign in attempts to undermine the election.

"There’s nothing in the story this morning that is surprising to me, I think especially since the assessment came out in January," Kaine said. He later added Flynn's resignation "makes it virtually impossible now for the administration or the GOP in Congress to stop the investigation or sweep it under the rug."

Asked whether he thought these contacts affected the outcome of the election, Kaine said, "Let’s get to the bottom of it, answer all the questions and then we’ll know that."

Several senators, including Sens. Jeff Flake, R-Ariz., and McCain, expressed concern about the state of affairs at the White House. Faced with questions about whether President Trump could overcome the turmoil, several Republican senators wouldn't give a clear answer, instead saying it's something the president must work on.

"That’s what they’ll have to work on achieving," said Sen. Marco Rubio, R-Fla. "I think every administration -- obviously this is a unique situation that we’re now facing -- but every administration early on faces some turbulence. This is perhaps a little more turbulent than we’ve been accustomed to in the past."

"It has to happen or otherwise we don’t function properly. So, I’m gonna say I’m sure they can if they wish to," said Sen. Bob Corker, R-Tenn. "We all wish them well as we collectively try to deal with America’s problems."