Story highlights Khizr Khan asked Sen. John McCain to withdraw his support for Trump

Khan has become one of Trump's most vocal critics since his speech at the Democratic convention

Washington (CNN) Khizr Khan is calling on Sen. John McCain to withdraw his support for Donald Trump because of his comments about the Gold Star parents whose son was killed in Iraq.

"I implore Sen. McCain ... I continue to implore all of the good Republicans who either support or are going to vote for their party's candidate, this will be a historic moment in the Republican Party," Khan told Cronkite News Tuesday

"If you publicly rebuked him, you will look back and you will stand tall in front of the nation," he added.

Khan, who has become one of the most successful critics of Trump, told the Arizona State University news service that McCain has been "my and my family's hero" and recalled talking with his son, Capt. Humayun Khan, about McCain's service shortly before he was killed in Iraq.

McCain blasted Trump after he criticized both Khizr Khan and his wife, Ghazala. But McCain, like many the other Republicans who have criticized Trump, has also declined to withdraw his support for the Republican nominee.

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