Iowa Senator Chuck Grassley is taking President Trump to task for Trump’s public criticism of his White House chief of staff.

In a weekend interview, Trump spoke negatively of General John Kelly’s job performance and suggested he may be considering firing Kelly or that Kelly might want to leave on his own. Grassley says Trump’s comments were inappropriate.

Grassley says, “The words that are used are very important and those words have been disrespectful of a person that defended our country and was a leader of the U.S. Marines for 46, 47, 48 years.” Kelly retired from the U.S. Marine Corps in 2016. In his tweet, Grassley said: “I wish President Trump would never discuss any ill feelings he has about his chief of staff, General Kelly.”

Grassley notes, the president is certainly entitled to make any changes in his staff he sees fit, but he shouldn’t be speculating about those individuals on national TV. Grassley says, “The president could fire him for justified reasons, the president could praise him for justified reasons, but those sorts of words should never go public.”

In a weekend interview on Fox News, Trump said he isn’t happy with Kelly’s performance as chief of staff: “Certain things I love that he does and there are certain things I don’t love,” Trump said. “There a couple of things that just aren’t his strength. It’s not his fault, it’s not his strength.”