Police Commissioner Richard Ross says 72 Philadelphia cops have been placed on administrative duty amid an initial investigation into a national group's accusation of officers in at least five states posting racist and anti-Muslim comments on social media.

Ross said he believed at least 'several dozen' people would be disciplined and he expects some to be fired. The commissioner said the internal affairs division prioritized posts 'clearly advocating violence or death against any protected class such as ethnicity, national origin, sex, religion and race.'

An independent law firm had been hired to determine whether posts were constitutionally protected before any discipline is imposed.

Philadelphia Police Commissioner Richard Ross speaks with members of the media during a news conference in Philadelphia on Wednesday

'I am not prepared to tell you at this point who's being disciplined and how many may be terminated, but I can tell you with a degree of certainty there are some people who will meet with that fate,' Ross said Wednesday.

John McNesby, president of the Philadelphia police union, said the Fraternal Order of Police leadership and attorneys will protect the officers' free speech.

'It's premature and irresponsible for the commissioner to tell the public that police officers will be fired without a complete investigation into officers' social media use,' he said in an emailed statement. 'Our officers are entitled to due process just like any other citizen.'

Activist demand the removal of 330 officers from street duty on June 7 at a protest at Philadelphia's Police Headquarters after Commissioner Richard Ross announced an outside law firm would review the Plain View Project's social media database

The posts were uncovered by the Plain View Project, a team of researchers who spent two years looking at the personal Facebook accounts of police officers from Arizona to Florida.

They said they found officers bashing immigrants and Muslims, promoting racist stereotypes, identifying with right-wing militia groups and, especially, glorifying police brutality. All the posts were public.

'We've talked about, from the outset, how disturbing, how disappointing and upsetting these posts are, and they will undeniably impact police-community relations,' Ross said.

'There's no question that this puts us in a position to work even harder than we already do to cultivate relationships with neighborhoods and individual groups who we struggle to work with or struggle to maintain relationships with now.'

Ross also announced other steps, including measures to monitor social media posts by officers, anti-bias training for officers and preparation of a training video.

'I can't think of any other investigation that we've undertaken, at least in my 30 years, where that many people were taken off the street at one time,' Ross said. He said he was a 'dinosaur' who didn't use social media, but he couldn't understand how police officers who come into contact with many different people - and who were themselves part of a diverse recruiting class - could make what he called 'ridiculous assertions' about whole groups of people.

Ross: 'I am not prepared to tell you at this point who's being disciplined and how many may be terminated, but I can tell you with a degree of certainty there are some people who will meet with that fate'

'It really makes me sick, because we are in a position to know better, we are in a position by virtue of what we do every day, and how many people you see in different walks of life that people are the same - people want the same thing out of life,' he said.

'It angers me beyond belief, because it just makes our job far more difficult than it needs to be.'

Earlier this month, St Louis police revealed they are conducting an investigation into similar allegations.

The team of researchers who uncovered the posts said that forty-three of the 3,500 accounts viewed by the group were tied to St Louis, with 22 of those involving current officers.

The Missouri chapter of the Council on American-Islamic Relations (CAIR) responded by demanding city police undergo sensitivity training.

According to the St Louis Post-Dispatch, Ron Hasty, a St Louis sergeant is named by the Plain View Project in connection with the Facebook profile 'Ron Nighthawk'.

There are at least 30 posts that appear under the Nighthawk name within the Plain View Project's site.

Hasty, who is the head of the city’s trash task force, told the newspaper: 'I’m not a racist. You can talk to any of my friends.'

St Louis police are conducting an internal investigation into allegations that current and former officers posted racist, violent, homophobic and anti-Muslim statements (right) on Facebook

A Philadelphia-based organization called the Plain View Project studied thousands of posts (pictured) from St Louis and seven other jurisdictions as part of a project that began in 2017

Between 2006 and 2007, Hasty won two Medal of Valor awards from Crusade Against Crime.

He was also named the St Louis Police Department’s Officer of the Year in 2006.

The project also lists the officers' salary and their positions online. Hasty makes more than $70,000 as a sergeant.

Jeff Roorda, business manager of the St Louis Police Officers' Association, said the union is trying to set up a meeting with CAIR.

'Until the source of the posts is verified and authenticated, we're not going to comment on any speculation that any of these posts originated with police officers who we represent,' he said in a written response to questions.

Krewson said in a statement that the city's social media policy adopted last September makes it clear such posts are unacceptable.

'We expect professionalism out of every City employee,' she said.