Americans are in danger of ignoring casual lies by President Trump, making him a bigger threat in a sense than Russian actors trying to interfere in U.S. elections, according to former FBI Director James Comey.

“I’m sure Russia is engaged in efforts to undermine all manner of American institutions, but the president of the United States tweets lies about those institutions nearly every day," Comey said Thursday at a Hewlett Foundation event near San Francisco. "He does it so often that we’ve become numb to it. And there’s danger in that numbness."

Trump fired Comey in May 2017 over what he later said was an effort to shut down a probe into Russia's interference in the 2016 campaign. Since then, the president has regularly targeted Comey for criticism over Twitter.

"I wake up some mornings and the president’s tweeted I should be in jail. You know what I do? I laugh and I go, ‘Oh, there he goes again.’ I don’t follow him on Twitter, so I only see it if one of you retweets it. But I laugh. And that laughing is dangerous.”

Comey also disputed Attorney General William Barr's claim that the Obama administration spied on the Trump campaign in the 2016 presidential election.

“I don’t understand what the heck he’s talking about,” Comey said. “But when I hear that kind of language used, it’s concerning because the FBI and the Department of Justice conduct court-ordered electronic surveillance. I have never thought of that as ‘spying.’"

[ Opinion: Byron York: Barr is right, spying on Trump campaign did occur]