Philadelphia Police Commissioner Richard Ross announced Thursday that 13 officers would be fired for making racist or offensive Facebook posts, an unprecedented wave of terminations resulting from a scandal that has attracted national attention.

Speaking alongside Mayor Jim Kenney at a news conference at Police Headquarters, Ross said that in addition to the firings — the largest number of officers dismissed at one time in recent city history — an additional 56 cops would face disciplinary actions ranging from a reprimand to a 30-day unpaid suspension.

“I continue to be very angered and disappointed by these posts, many of which, in my view, violate the basic tenets of human decency,” Ross said, adding that the department must “move past this ridiculous hate that just consumes this country and has done so for centuries.”

The disciplinary actions represent the most significant response yet to last month’s publication of the Plain View Project, a database compiled by advocates that catalogs Facebook posts allegedly made by officers in Philadelphia and seven other jurisdictions across the country.

Still, some details of the city’s response remained unclear.

Ross, flanked by his five deputy commissioners, did not identify any of the officers to be fired, saying that the paperwork had not yet been completed and that “a couple” of the affected officers were on vacation. The highest rank among those to be fired is sergeant, Ross said.

He also did not identify specific posts that may have led to termination, but did say that officers losing their jobs had posted material condoning violence, encouraging police brutality, or promoting memes or other content that was anti-Islamic, homophobic, or racist.

As one example, Ross cited the words “Death to Islam.” That phrase appeared in a post allegedly made by Sgt. Joseph Przepiorka. It was not known Thursday whether Przepiorka was among the 13 officers to be fired. The Plain View Project said Przepiorka made 91 questionable posts, 56 of which were categorized as showing bias.

The police union, which already had expressed opposition to firing officers over the posts, said it was preparing “an appropriate response to protect our members’ rights.”

John McNesby, president of Fraternal Order of Police Lodge 5, said in a statement: “FOP Lodge No. 5 and our members condemn racist and hateful speech in any form. The overwhelming majority of our members serve this city with integrity and professionalism.”

Kenney said at the news conference that he found many of the posts “deeply disturbing,” but he defended Ross’ leadership, calling the disciplinary measures “a positive step.”

“Building trust in the communities we serve will always be our top priority,” Kenney said. “We will not allow this terrible incident to break down the progress we’ve made, and we pledge to do better moving forward.”

Ross said last month that 72 officers had been taken off street duty pending the department’s investigation into the more than 3,000 posts allegedly made by about 330 active officers.

The department’s Internal Affairs division then began working with the law firm Ballard Spahr to review each post and evaluate whether it was constitutionally protected speech under the First Amendment, or if it violated departmental policies.

On Thursday, Ross said that 69 of those 72 officers were found to have posted material worthy of discipline, which he described as statements that “erode the trust necessary for a police department to carry out its core mission.” The range of punishments was “based upon the gravity of the offense,” Ross said.

The vast majority of officers facing discipline — 52 — will face punishment topping out at a five-day suspension, Ross said. He said their posts may have been crude or offensive or advocated excessive force, but not necessarily because of race, gender, or ethnicity.

A second group of 17 cops made posts that Ross said were “not only offensive,” but demonstrated “that the officers have little or no regard for their position.”

Of that group, Ross said 13 would face termination, while the other four would be suspended for 30 days. Ross did not explain why some of the apparent worst offenders would not lose their jobs, but said they already had undergone training on social media and professionalism.

City Solicitor Marcel Pratt said after the news conference that the Police Department ultimately was able to judge how “disruptive” the posts were to its ability to function or develop relationships with community residents.

Ross said the investigation into the other 260 or so active officers on the Plain View Project’s database was ongoing. He said he believed those officers had made less offensive posts, and he did not anticipate further firings.

He also said the entire department would undergo antibias training this fall.

Asked after the news conference if the Police Department had a problem with racism, Kenney said: “I think the country has an issue with racism, and [the department is] no different than any other citizen of this country, from the commander-in-chief on down.”

He said police would work to improve recruiting and training in an effort to eradicate bias in the department, and added: “I do believe that [police] should be held to a higher standard because of the responsibility they have in law enforcement.”

Ross said the department would work to regain the trust of city residents.

Still, he acknowledged that the scandal would “undoubtedly” leave a mark on the department’s reputation.

“This takes us back,” he said. “There’s no question.”