Fort Bragg, North Carolina, the Army’s most populated installation, spent half a day in the literal and proverbial dark April 25 as part of an exercise designed to stress test the post in the face of a cyberattack.

By Thursday midday, officials announced that the power outage, which spared Womack Army Medical Center and the Soldier Support Center, was only a drill, issuing an apology later that day.

“We understand the exercise conducted caused concern for many within our community and surrounding areas ... for that, we apologize,” officials said in a Facebook post.

Good afternoon all! We understand the exercise conducted caused concern for many within our community and surrounding...

Posted by Fort Bragg, N.C. on Thursday, April 25, 2019

The idea, according to a statement, was to simulate how the installation would handle a cyberattack against the power grid as a brigade prepared for deployment.

“Department of Defense requires military installations to conduct readiness exercises on an annual basis,” the post said. “The intent is to determine the readiness and resiliency of the installation in a real-world scenario. With that said, our objectives have been met and as many of you know, everything is back to normal.”

Fort Bragg’s Facebook page had posted periodic updates throughout the outage, racking up hundreds of comments from bemused and concerned soldiers and family members alike.

“Did you all forget that very recently a foreign national tried to access Fort Bragg?” Tina Vandivier wrote on Saturday. “Those soldiers and guards TRAIN for that same scenario. A spoiled gallon a milk is a small price to pay to check and see how prepared we really are.”