A Philadelphia Fire Department paramedic has apologized for posting on Instagram a photo of two black men pointing handguns at a white police officer under the caption: "Our real enemy."

Paramedic Marcell Salters continued from there: ". . . need 2 stop pointing guns at each other & at the ones that's legally killing innocents."

Mayor Nutter on Thursday said he condemned the behavior "in the strongest possible terms," calling its message "reprehensible."

"We celebrate the exercise of our First Amendment right to expression," Nutter said, "but there are clear limits, and this posting went far beyond standards of decency. Inflammatory speech or behavior like this is simply irresponsible and could potentially incite others to inappropriate actions."

Salters, who works for Field Medic Unit 23 at 1201 N. 61st St., could not be reached for comment Thursday.

He did, however, apologize for the post on his Facebook page.

"That post was out of anger of what is going on around the world," he said, specifically mentioning the deaths of Michael Brown and Eric Garner, black men who died at the hands of white police officers, along with his own experiences with police.

The image he posted is from a music video for a song by the rappers Uncle Murda and Maino called "Hands Up," which the men wrote after the deaths of Brown and Garner.

Salters said his post was not meant to hurt anyone, including the police, whom he called his "brothers in blue."

Yet in a since-deleted Facebook comment Salters said he "never did or will like police."

"Because of what i do i have to work with them but dont have to like them," he said. ". . . There are numerous crooked & corrupted cops (mostly white) & mostly they harass, beat, or kill innocents(mostly blks)."

Joseph Schulle, head of the firefighters' union Local 22, issued a statement Thursday afternoon that said that during "this difficult time" the union members stand "shoulder to shoulder with our brothers and sisters in blue."

"Not only do we work together in the street, but I count many police officers as good friends, as well as family," Schulle said. "Again, most of the members of the Philadelphia Fire Department would most certainly echo these sentiments."

The statement did not mention Salters or the Instagram post, and Schulle later said he did not want to discuss the post at length except to say the vast majority of the union's members don't agree with the sentiment.

Nutter said he has asked Fire Commissioner Derrick Sawyer to conduct an investigation. He said any disciplinary actions against the paramedic would be made after that investigation is complete.

Schulle said he expected Salters would be disciplined because he made a comment about the post while on duty. He said the paramedic was off-duty when he made the initial Instagram post.

"You get into a gray area when you start discussing First Amendment rights and responsibility as a city employee," he said. "I think that's what the department has to weigh in determining what type of punishment will be issued."

215-854-2730 @TriciaNadolny

Inquirer staff writer Chris Hepp contributed to this article.