SAN DIEGO -- An investigation is underway into a social media post attributed to two Camp Pendleton Marines that showed a uniformed serviceman with a rifle and was captioned "Coming to a gay bar near you!"

The post, which appeared to have originated on Snapchat, was added to a closed Facebook group called Camp Mendleton resale just days after a gunman, 29- year-old Omar Mir Seddique Mateen, opened fire at Pulse nightclub in Orlando, Florida, early Sunday, killing 49 people and wounding dozens more.

The post was accompanied by the caption "Too soon?" the Marine Corps Times reported. The post has since been deleted.

A statement from I Marine Expeditionary Force at Camp Pendleton said authorities were investigating the "threatening" post and would take appropriate action.

"The Marine Corps does not tolerate discrimination based on sexual orientation, race, gender or religion. 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," according to the statement.

I MEF spokesman 1st Lt. Thomas Gray told the Marine Corps Times the corporal in the photo had been identified, as had the one who posted it to Facebook. Their names were not made public.

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