A possible active shooter was reported at a U.S. Army installation in Alabama on Tuesday, forcing the facility to go on lockdown, Fox News reports.

Via Fox News:

The Redstone Arsenal in Huntsville issued the alert on Twitter of a “possible active shooter on the Arsenal.”

The tweet continued, “Installation is on lockdown. Run, hide, fight.”

An email was sent out to employees at the Redstone Arsenal at 10:31 a.m. informing them that this was “a real world event, which is not part of the exercise,” according to AL.com. The facility reportedly was conducting active shooter drills this week.

TRENDING: BREAKING REPORT: President Trump to Nominate Amy Coney Barrett to Replace Ginsburg on the Supreme Court

“The facility is under lockdown and all gates are closed,” the email continued.

Redstone Arsenal’s public affairs told Fox News that all gates into and out of the post are closed.

A spokesperson told AL.com that there are no confirmed casualties at this time, but they are still investigating the situation.