Two active-duty Marines are under investigation in connection to a social media post purportedly threatening to attack gay bars following Sunday's deadly mass shooting in Florida.

The California-based I Marine Expeditionary Force launched a command investigation after a photo surfaced on social media showing a corporal in uniform holding a rifle with his finger near the trigger. The words "Coming to a gay bar near you!" appear at the bottom of the photo .

The picture was posted recently to Camp MENdleton resale, a closed Facebook group for male Marines with more than 25,000 members. The person who purportedly posted it also wrote "Too soon?"

The post follows Sunday's terror attack on a gay nightclub in Orlando, Florida, that killed 49 people and left 53 wounded.

First Lt. Thomas Gray, a spokesman for I MEF, told Marine Corps Times that the command has identified the Marine in the picture and the one who posted it on Facebook.

" We cannot discuss details of an ongoing investigation, but I can tell you the command is taking this incident seriously," Gray said .

Marine officials have vowed to take "appropriate action" in response to the social media post, according to a statement released by I MEF.

"The Marine Corps does not tolerate discrimination based on sexual orientation, race, gender or religion," the statement says. "...This type of behavior and mindset will not be allowed, and it is not consistent with the core values of honor, courage and commitment that are demonstrated by the vast majority of Marines on a daily basis."

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Michael Moss, the founder of the Camp MENdleton resale Facebook group, said on Facebook that the post was deleted as soon as it was reported, and the person was banned from the group immediately.

"We do not tolerate hate speech," he said. Moss was not immediately available for comment.

A command investigation has been launched into the Marine in the picture and the one who posted it, said I MEF spokesman 1st Lt. Thomas Gray, who did not identify either man.

"As you know, we cannot discuss details of an ongoing investigation, but I can tell you the command is taking this incident seriously," Gray said in an email to Marine Corps Times.

In a statement, I MEF vowed to take "appropriate action" in response to the social media post.

The incident coincides with a separate investigation by the FBI and San Diego police into an anonymous threat posted Tuesday on the men-seeking-men section of the Craigslist San Diego personal ads, according to local television station KGTV.

"Orlando was long overdue," the post stated, according to ABC affiliate. "...San Diego you are next."