FILE - U.S. Rep. Justin Amash of Michigan

U.S. Rep. Justin Amash of Michigan

U.S. Rep. Justin Amash told CNN Sunday that high-ranking Republicans have thanked him privately for calling for the impeachment of President Donald Trump.

Speaking to Jake Tapper on "State of the Nation," Amash said Republicans should be able to speak their minds publicly about Trump.

"I get people sending me text messages, people calling me, saying 'thank you for what you're doing,'" Amash told Tapper. "They're not saying it publicly. And I think that's a problem for our country, it's a problem for the Republican Party, it's a problem for the Democratic Party when people aren't allowed to speak out."

On Independence Day on Thursday, Amash announced he was leaving the GOP because of the party's failure to hold Trump accountable.

"Today, I am declaring my independence and leaving the Republican Party," Amash wrote Thursday in an op-ed published by The Washington Post. "No matter your circumstance, I'm asking you to join me in rejecting the partisan loyalties and rhetoric that divide and dehumanize us. I'm asking you to believe that we can do better than this two-party system – and to work toward it. If we continue to take America for granted, we will lose it."

Amash didn't mention Trump by name in his Thursday announcement, but he called the president out during Sunday's interview with CNN.

"What the president is doing is actually lowering the tone across the country, he's harming civil discourse, he's creating a lot of partisan divide. He's enhancing it," Amash said. "And I think that's very dangerous for our country and I don't think a lot of people appreciate it."

Amash also wouldn't rule out a third-part run for president when asked by Tapper.