Washington (CNN) Former National Economic Council Director Gary Cohn said he's "concerned" there is no one left in the White House to stand up to President Donald Trump and tell him "what he doesn't want to hear."

"We had an interesting nucleus of people when I was in the White House -- the initial team. We were not bashful. It was a group that was willing to tell the President what he needed to know, whether he wanted to hear it or not," Cohn told CNN's David Axelrod in an interview on "The Axe Files" podcast released Monday.

"None of us are there any more. So I am concerned that the atmosphere in the White House is no longer conducive, or no one has the personality to stand up and tell the President what he doesn't want to hear," he said.

Cohn resigned from his position as Trump's top economic adviser in March 2018 in the wake of his fierce disagreement with the President's decision to impose tariffs on steel and aluminum imports. His exit sounded alarm bells in establishment circles in Washington and on Wall Street, where many viewed the former Goldman Sachs executive as a steadying influence on economic policy inside the Trump White House.

Cohn's comments echo remarks from former White House chief of staff John Kelly in October when he said he had warned the President before he left the White House not to hire a replacement who wouldn't tell him the truth or tell he that he wouldn't be impeached.

"I said, whatever you do — and we were still in the process of trying to find someone to take my place — I said whatever you do, don't hire a 'yes man,' someone who won't tell you the truth — don't do that," Kelly said.

Reflecting on his role in the White House, Cohn said he thought he would be able influence Trump more within his administration than in an outside capacity.

"I thought I could potentially sway him, and I also know, historically, that sometimes what you run on is not exactly what you mean when you come to govern," he said. "In my mind, having a seat on the inside and trying to influence was better than being on the outside and trying to get to a more positive outcome on, you know, climate, on trade, on immigration."

Cohn added: "I come from a fact-based world. If I can empirically show you facts and I can show you reality, that's supposed to win the day."

"I went in overly prepared with factual analysis, and in many respects, look, it may not have ended up where I wanted it to end up, but he's the ultimate decision-maker," he said. "I'm supposed to do my job and make sure that he understands the impact of that decision."