Muslim American Khizr Khan, whose son Humayun was killed while serving in the U.S. Army, offered Republican candidate Donald Trump his copy of the Constitution during a speech at the Democratic convention. (The Washington Post)

Khizr Khan, the Gold Star father who lambasted Donald Trump at last year’s Democratic National Convention, on Sunday criticized the now-president’s chief of staff for his handling of the controversy over Trump’s military condolence calls.

Khan said John F. Kelly, a retired four-star Marine general, had “made the situation even worse” by defending Trump and joining him in attacking Rep. Frederica S. Wilson (D-Fla.) after she criticized Trump’s call to the widow of one of four service members killed in an ambush in Niger.

“Instead of advising the president that restraint and dignity is the call of the moment, former general Kelly indulged in defending [the] behavior of the president and made the situation even worse,” Khan said during an appearance on CBS’s “Face the Nation.” “Our political leaders, elected by the people, are deserving of equal dignity and equal respect instead of being maligned on misstated facts. And that was beyond the call of the moment.”

During an appearance before reporters Thursday, Kelly called Wilson an “empty barrel” and falsely claimed that she had taken credit for securing funding of a federal building in a 2015 speech.

Khan, who is promoting a new book, also criticized Kelly's handling of Trump’s response to a deadly melee in Charlottesville at a gathering organized by white supremacists in August.

“I was shocked — I was shocked —to see citizen Kelly standing next to the president when … the president could not have the proper words to condemn the attack on the blessed city of Charlottesville, Virginia, by neo-Nazis,” said Khan, a resident of Charlottesville.

Khan’s son Humayun Khan was killed in Iraq in 2004. While speaking at the Democratic convention last year, the elder Khan challenged Trump, at one point saying, “You have sacrificed nothing and no one.” He also held up a pocket-size copy of the U.S. Constitution, asking whether Trump had read it.

Kelly is also a Gold Star father. He lost a son, Robert M. Kelly, in Afghanistan seven years ago.