Dallas residents were jolted out of bed late Friday evening after a hacker triggered all the city's emergency sirens, setting off a wave of panic and confusion.
As the system is rebooted, officials said it is likely some sirens will go off again and asked the public to ignore them over the next day or two.
Officials now report that the system was hacked, forcing crews to shut down the warning system that would normally alert residents to severe weather dangers.
WFAA, Dallas' sister station of KSDK, viewers began reporting the sirens at around 11:44 p.m. Friday. Office of Emergency Management Director Rocky Vaz said his office had to eventually shut down the system.
Residents took to social media using #DallasSirens to express frustration, confusion and a little humor.
Louis C.K. has absolutely torn Donald Trump's presidency apart
Louis didn't expect his words to become front page news, but he doesn't regret his fiery diatribe against the candidate. They lie a lot. "Look if you voted, that's the guy he lied to", he said.
City spokeswoman Sana Syed said Saturday that hacking is one of the possible causes investigators are considering. "We will work to identify and prosecute".
Technicians were trying to determine how to bring the system back online without the risk of it being hacked again, he said.
Dallas City Fire and Rescue had to visit each individual siren site to manually turn them off.
Please don't call about the tornado sirens sporadically sounding in Dallas. We won't know the health of our sirens until we reactivate the system.
"This is yet another serious example of the need for us to upgrade and better safeguard our city's technology infrastructure", he posted on Facebook. "Making the necessary improvements is imperative for the safety of our citizens", Mayor Rawlings said.