WATCH: Sen. Flake: “More doubtful” North Korean summit will happen 

Sen. Jeff FlakeJeffrey (Jeff) Lane FlakeFlake threatens to limit Trump court nominees: report Poll: McSally holds 14-point lead in Arizona GOP Senate primary GOP senators introduce bill to prevent family separations at border MORE (R-Ariz.), a frequent critic of President Trump, says he’s “more doubtful” that the planned meeting between the president and North Korean leader Kim Jong Un, slated for June 12 in Singapore, will happen.

“I don’t know — it looks more doubtful to me,” Flake told The Hill when asked if he thinks the summit will happen, adding, "But you know, I'm glad that we are talking. I’ve never put much hope in that meeting.”

Flake's comments come as North Korea warned earlier this week that it could pull out of the summit due to military exercises by the U.S. and South Korea.

Flake added that he thinks it takes more than one month of “prep work” for a meeting of “that significance.” 

Fellow GOP Sen. Rob PortmanRobert (Rob) Jones PortmanSenate moving ahead with border bill, despite Trump 13 GOP senators ask administration to pause separation of immigrant families Lawmakers, businesses await guidance on tax law MORE (Ohio) was more optimistic that the Korean summit will go forward despite North Korea’s threats.

“Do I trust them? No,” Portman said, “Do I want to talk with them directly government to government? Yes. And I think we can move forward on that.”

House Armed Services Committee member Rep. Steve Russell (R-Okla.) told The Hill he also predicted “the meeting will still occur,” even if Kim sounds off ahead of time. 

“I guess he doesn’t want to look like a doormat — he’s trying to sound tough or whatever it might be prior to the negotiations — OK, we can live with rhetoric, we can live with that,” Russell said.

Click on the video above to hear the lawmakers in their own words.