The man who attacked the U.S. Centers for Disease Control (CDC) headquarters in Atlanta on Friday fired more than 180 shots and broke about 150 windows, piercing "blast-resistant" panes and spattering glass shards into numerous rooms, according to information circulated internally at the agency.

It may take weeks or even months to repair and clean up the damage, CDC personnel said.

A Georgia man who had blamed the COVID-19 vaccine for making him depressed and suicidal opened fire late Friday, killing a police officer. No one at CDC was injured.

The shooter was stopped by CDC security guards before driving to a nearby pharmacy, a law enforcement official said. The official wasn't authorized to publicly discuss the investigation and spoke on condition of anonymity. The 30-year-old man, Patrick Joseph White, later died, but authorities haven't said whether he was killed by police or killed himself.

Multiple buildings hit 

The CDC's director, Susan Monarez, said online that said at least four of the agency's buildings were hit in the attack.

The extent of the damage became more clear during a weekend CDC leadership meeting. Two CDC employees who were told about what was discussed at the meeting, described details on condition of anonymity because they weren't authorized to reveal the information. Details were also in an agency memo seen by an Associated Press reporter.

Building 21, which houses Monarez's office, was hit by the largest number of bullets. CDC officials did not say if her office was hit.

CDC employees were advised to work from home this week. 

'All potential threats' being monitored

The U.S. Department of Health and Human Services (HHS) says it continues to support CDC personnel and that additional safety and security measures are being put in place ahead of their return to the office.

Both local and federal law enforcement are "conducting intensive monitoring of all potential threats to CDC and its staff," the agency's acting chief operating officer Christa Capozzola said in an email to staff over the weekend.

She said work was under way to clean up and repair extensive damage to the CDC's campus by the shooter who, according to the investigation so far, acted alone.

An "all-staff" meeting on Tuesday will become a virtual-only event, Monarez said in a separate email. The agency's safety division asked employees in an email to remove CDC-identifying decals from their vehicles.

A retired CDC official, Stephan Monroe, said he worried about the long-term impact the attack would have on young scientists' willingness to go to work for the government.

"I'm concerned that this is this is going to be a generational hit," said Monroe, speaking to a reporter near the corner where a poster had been set up in honour of David Rose, the officer who was killed.

U.S. Health and Human Services Secretary Robert F. Kennedy Jr., was a leader in a national anti-vaccine movement before U.S. President Donald Trump selected him to oversee federal health agencies, and has made false and misleading statements about the safety and effectiveness of about COVID-19 shots and other vaccines.

Years of false rhetoric about vaccines and public health was bound to "take a toll on people's mental health," and "leads to violence," said Tim Young, a CDC employee who retired in April.

Dr. Jerome Adams, the U.S. surgeon general during Trump's first administration, said Sunday that health leaders should appreciate the weight of their words.

"We have to understand people are listening," Adams told Face the Nation on CBS. "When you make claims that have been proven false time and time again about safety and efficacy of vaccines, that can cause unintended consequences."

The union representing CDC workers said the violence "compounds months of mistreatment, neglect, and vilification that CDC staff have endured," adding that "the deliberate targeting of CDC through this violent act is deeply disturbing, completely unacceptable, and an attack on every public servant."