By Jennifer Rizzo, CNN

Washington (CNN) - Fort Jackson officials said Friday that an atheist soldier was asked to lower their head during a prayer portion of a graduation ceremony rehearsal, but then decided it was ok for the soldier to stand at Attention.

The 20-year old private first class, a proclaimed atheist, graduated from Advanced Individual Training at Fort Jackson in South Carolina on Thursday.

The soldier, who requested that CNN not give a name and gender for fear of repercussions, called the Military Religious Freedom Foundation on Wednesday after taking part in a rehearsal for the graduation.

The soldier told the watchdog group that during the rehearsal, officials ordered the soldiers to bow their heads and clasp their hands during the chaplain's benediction. As an atheist, the soldier refused to do so.

"I immediately pointed out that not only is a prayer at a public ceremony unconstitutional, but to force someone to give the illusion of religion when the individual does not believe in any religion is blatantly wrong and very illegal," the soldier said in an e-mail to the foundation.

The rest of the platoon "groaned" at the soldier's stance, but the soldier wrote that "I stood my ground."

"When you stand up like this, you make yourself a tarantula on a wedding cake," said Mikey Weinstein, founder of the foundation. Weinstein said the soldier was "brave" for taking a stand.

Officials at Fort Jackson threatened to pull the soldier from the ceremony but then backed down, according to the soldier, after hearing that the soldier had contacted the religious freedom foundation.

"This is an absolute perfect example of the separation of church and state, and it takes a 20-year-old to stand up and say no," Weinstein said.

Fort Jackson officials told CNN a non-commissioned officer informed the soldier to bow their head for uniformity purposes but says there was never a requirement to pray during the prayer portion of the graduation.

When the soldier refused, citing a Supreme Court ruling that states there was no requirement to pray in public ceremonies, the officer then took the matter to the platoon sergeant, who also told the soldier to bow their head for uniformity purposes, according to Patrick Jones, a Ft. Jackson Public Affairs Officer.

Upon refusing again, the platoon sergeant contacted the company commander who then told the soldier that there was no requirement to pray or bow ones head, but was required to remain at “attention”, Jones stated.

“It is not the command’s policy to force anyone to bow their heads and clasp their hands to pray,” said Jones. “The Army fully recognizes all faiths or lack there of”.

The graduation ceremony was conducted without incident, Jones said