Story highlights "There's no excuse. Ever," Gingrich said

"He's got to become much more disciplined," Gingrich added

Washington (CNN) Former House Speaker Newt Gingrich, a top ally of Donald Trump, criticized the GOP nominee Friday night for his overnight Twitter rampage against Hillary Clinton and her campaign.

"You can't tweet at 3 o'clock in the morning. Period. There's no excuse. Ever. Not if you're going to be president of the United States," Gingrich told Fox News' Sean Hannity.

"What Trump has got to understand, he's got to sing either, 'I got to be me' or he's got to order a new song, 'I've got to be President.' They're not the same song. He's got to become much more disciplined," Gingrich said about Trump's behavior. "For a while there, I thought he had really turned a corner. This last week, I think has been, frankly, a lost week. A week which has hurt him. Which has shaken his own supporters."

Trump's week began with a widely criticized performance at Monday's debate, which led to a dip in poll numbers. His rant early Friday morning specifically focused on Alicia Machado, a former Miss Universe whom Trump has criticized about her weight gain in the 1990s. Machado is now a highly visible surrogate for Clinton, and the feud threatens to harm Trump's standing even further with groups with which he has already struggled: women and Hispanics.

This isn't the first time Gingrich -- once floated as a possible running mate for Trump -- has criticized Trump. After Trump accused U.S. District Judge Gonzalo Curiel, who was overseeing a lawsuit involving Trump University, of bias because of his Mexican heritage, Gingrich called him out.

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