CNN Worldwide President Jeff Zucker on Wednesday tore into President Trump Donald John TrumpBiden says voters should choose who nominates Supreme Court justice Trump, Biden will not shake hands at first debate due to COVID-19 Pelosi: Trump Supreme Court pick 'threatens' Affordable Care Act MORE and White House press secretary Sarah Huckabee Sanders for their sustained attacks on the press after the network's New York City office received an explosive device in the mail.

"There is a total and complete lack of understanding at the White House about the seriousness of their continued attacks on the media," Zucker said in a statement.

"The President, and especially the White House Press Secretary, should understand their words matter," he added. "Thus far, they have shown no comprehension of that."

Statement from CNN Worldwide President Jeff Zucker: pic.twitter.com/OXyIT6oSLT — CNN Communications (@CNNPR) October 24, 2018

CNN employees evacuated the network's Manhattan offices at the Time Warner Center on Wednesday morning after a suspicious package was found in the mailroom. The item was addressed to former CIA Director John Brennan John Owen BrennanJournalism or partisanship? The media's mistakes of 2016 continue in 2020 Comey on Clinton tweet: 'I regret only being involved in the 2016 election' Ex-CIA Director Brennan questioned for 8 hours in Durham review of Russia probe MORE, who works for NBC News as a contributor and has appeared on CNN.

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The package was determined to contain an explosive device similar to ones addressed to former President Obama, Hillary Clinton Hillary Diane Rodham ClintonThe Memo: Trump furor stokes fears of unrest Bloomberg rolls out M ad buy to boost Biden in Florida Hillicon Valley: Productivity, fatigue, cybersecurity emerge as top concerns amid pandemic | Facebook critics launch alternative oversight board | Google to temporarily bar election ads after polls close MORE and billionaire philanthropist George Soros.

Trump and Sanders both condemned the threats, with the president urging unity and announcing a "major federal investigation" was underway to determine who was responsible.

"I just want to tell you that in these times, we have to unify," Trump said at a White House event later Wednesday. "We have to come together and send one very clear, strong, unmistakable message that acts or threats of political violence of any kind have no place in the Untied States of America."

Trump did not specifically mention any of the individuals who were targeted on Wednesday, despite explicitly criticizing each of them throughout his presidency.

Sanders denounced threats against CNN and public officials in a separate statement.

"These terrorizing acts are despicable, and anyone responsible will be held accountable to the fullest extent of the law," she said.

This is an ongoing situation that President Trump and his admin are monitoring closely. Our condemnation of these dispicable acts certainly includes threats made to CNN as well as current or former public servants. These cowardly acts are unacceptable and wont be tolerated. https://t.co/YbMbCUWMPC — Sarah Sanders (@PressSec) October 24, 2018

Trump has had a fraught relationship with the media dating back to his presidential campaign and extending into his tenure in the White House. The president often derides negative coverage as "fake news," and has, in recent months, repeatedly labeled the press the "enemy of the people."

That rhetoric has extended to Trump's campaign events, where the president routinely encourages supporters to jeer the media in attendance and supporters periodically break into chants of "CNN sucks."

The relationship between CNN and the Trump administration has been particularly contentious. The president has refused to take questions from White House correspondent Jim Acosta at multiple press conferences, attacking the network while doing so.

Sanders and Acosta regularly spar during White House press briefings, including a particularly intense clash over the administration's separation of migrant families.

The White House banned CNN reporter Kaitlan Collins from attending an open press event in July after she pressed Trump over his relationship with his former attorney Michael Cohen during a meeting with the head of the European Commission.

When questioned about those confrontations, the White House has repeatedly insisted that it's committed to a free press.