Lt. Col. Robin Ochoa, an Army spokeswoman, told Military.com that the app is considered a cyber-security threat.
Earlier this month, in a cyber awareness message, the Defense Information Systems Agency recommended that all employees of the Defense Department not use the Chinese-owned app.
"It is considered a cyber threat," Army spokeswoman Lt. Col. Robin Ochoa told Military.com. "We do not allow it on government phones."
A spokesperson for the U.S. Army did not immediately return a request for comment made by NBC News. A spokesperson for TikTok also did not immediately respond to a request for comment.
The initial guidance from the Pentagon to discontinue use of the app was part of an effort to "address existing and emerging threats," Pentagon spokesman Lieutenant Colonel Uriah Orland said in a statement, according to Reuters.
The app, owned by Chinese-base tech company ByteDance, came under scrutiny in October when Sens. Chuck Schumer of New York, the Democratic minority leader, and Tom Cotton, an Arkansas Republican, sent a letterto the acting Director of National Intelligence Joseph Maguire asking him to assess TikTok and other China-based companies for potential security risks.
In November, it was reportedthat a security risk assessment of TikTok by the U.S. government had been opened.
The Military had been using TikTok as a recruitment tool and as a way to reach young people, but began dissuading soldiers from using the app in mid-December, according to Military.com.
The Defense Department Cyber Awareness Message sent out earlier this month warned of "TikTok as having potential security risks associated with its use," and that those using the app should "be wary of applications you download, monitor your phones for unusual and unsolicited texts etc., and delete them immediately and uninstall TikTok to circumvent any exposure of personal information," according to Military.com.
However, military personnel are allowed to use the app on their personal devices, but the Defense Department has warned that those using the app in their private lives still exercise caution.
It was not immediately clear if the U.S. Marine Corps or the U.S. Air Force had also banned the app.