Emergency 911 phone and text services were reported down, at least temporarily, in multiple cities, Monday night.
The Minneapolis Police Department posted on Twitter that the outage occurred nationwide.
"ATTENTION: The 911 lines are not operational nationwide. This is for phone calls and text messaging. If you need police, fire or emergency medical assistance in Minneapolis, please call 612-348-2345. We will advise when this issue is fixed," the department said.
States affected appeared to be Minnesota, Delaware, Arizona, Indiana, Colorado, and Pennsylvania, Fox News reported.
Other departments tweeted that their 911 systems were down and provided alternate numbers, but most soon followed up with the message that the systems were back online.
"Delaware State Police Dispatch Centers are now operational and 911 calls are being received," Delaware State Police said. "If you call 911 and receive a busy signal or recorded message, callers are encouraged to text 911 and type your emergency in the message field or utilize the non-emergency telephone numbers."
Federal Communications Commissioner Jessica Rosenworcel said her agency needs to figure out what happened.
"The one system we need to work all the time is 911," Rosenworcel wrote on Twitter. "The FCC needs to get to the bottom of this now and figure out what is going on."