Iowa conservative firebrand Rep. Steve King said much of President Donald Trump’s base is getting “uneasy” about his inaction on immigration.

Speaking on Radio Iowa, King criticized Trump for picking “pro-immigration” economist Gary Cohn as an adviser.

“People are policy,” King said, “so whenever I see those kind of appointments come in place, I do get concerned about it.”

While King, a hardliner on immigration, said he was a fan of Attorney General Jeff Sessions, he wants Trump to take action on former President Barack Obama’s deferred action policies for undocumented immigrants and parents of American citizens.

“And I’ve told the president this: ‘Every day you don’t address this, it gets harder and harder to do,’” he said.

Trump, for his part, said dealing with Deferred Action for Childhood Arrivals is “very, very difficult subject for me” during a news conference in February, and that he wants to deal with the matter “with heart.”

“It’s one of the most difficult subjects I have because you have these incredible kids,” Trump said at the time.

King said if Trump doesn’t roll back Obama’s deferments, he could lose support from voters who put him in the White House. 

King said Trump has checked “quite a few” boxes behind campaign promises he made, but “There are a few to go or he will lose his base, and I think that’s an important message for the president to receive.”