Feelings were raw at the cable network because of a what it believed was a reluctance by the administration to discuss CNN as one of the targets of crude devices sent to political leaders, and the delivery of a fundraising email that attacked CNN that arrived in inboxes of supporters as the story unfolded. Trump's campaign later apologised for the email.
"The president, and especially the White House press secretary, should understand their words matter," said Zucker, president of CNN Worldwide. "Thus far, they have shown no comprehension of that." There was no immediate response from the White House.
The CNN attack was in one respect a case of mistaken identity. The package that included the explosive device and an envelope containing white powder was addressed to former CIA director John Brennan, a frequent Trump critic. Brennan is actually a contracted analyst at NBC News, although the package's street address was for the Time Warner Center in New York's Columbus Circle, where CNN's offices are.
CNN's Jim Sciutto and Poppy Harlow were on the air shortly after 10 am (local time), conducting a live interview about the devices sent to political leaders when the whooping sound of an alarm went off.
"Excuse me, that sounds like a fire alarm here. We'll keep you posted on that," Sciutto said. He continued the interview, but after one more question cut to a commercial.
After the break, he and Harlow were gone. They had evacuated, and correspondent Rene Marsh was hurriedly put on the air from a Washington studio. Wolf Blitzer, pulling in to the parking garage in Washington as this was happening, soon joined her.
Sciutto and Harlow then reported by phone from the street, then through a video stream, and then through a full CNN crew. CNN employees milled about in the streets, along with shoppers in the Time Warner Center mall, which was also evacuated.
Zucker was not among the evacuees. He was at the network's Atlanta headquarters on Wednesday, where he helped direct coverage from a control room.
CNN has been a frequent target of Trump's "fake news" barbs, and a "CNN sucks" chant broke out at a Monday campaign rally. Amid that backdrop, some at CNN were angered by an initial tweet by Sanders that condemned "the attempted violent attacks recently made against President Obama, President Clinton, Secretary Clinton and other public officials."
An hour later she sent another tweet that said the White House's condemnation "certainly includes threats made to CNN as well as current and former public servants." Trump, during an appearance at the White House on Wednesday afternoon, didn't mention CNN or any of the officials targeted by the device.
"No one is mentioning the name (CNN)," said network analyst Gloria Borger after Trump's appearance. "It's as if it can't roll off the tongue unless you're complaining about it."
Less than two hours after the CNN offices were evacuated, President Trump's campaign sent a fundraising email to some supporters that specifically targeted CNN and urging recipients to fight back against the "fake news' attacks and bias against hardworking Americans."
Campaign chairman Brad Parscale later apologised, saying it was a pre-programmed message that was not caught before news of the explosive device came out. Parscale said the campaign does not condone violence against CNN or anyone else.
CNN anchor Chris Cuomo, reporting from the street outside the Time Warner Center as employees began filing back in Wednesday afternoon, noted that he received messages of support online and from people he had seen since the news came out.
"You should take good where you find it," Cuomo said, "and you see a country that seems to be universally appalled by what has happened."