A glitch at the Baltimore 911 call center caused wait times of a minute or more for some callers reporting crimes and emergencies Monday night, city officials said.
The issue was resolved shortly before 11 p.m., the city's Office of Emergency Management announced.
Callers who got an answering machine were asked to stay on the line until a dispatcher picked up, while those who get a busy tone were told to hang up and call back.
"We're asking for your patience," said Scott Brillman, the city's acting 911 center director. "Please stay on the line."
Brillman said he didn't know what caused the phone problems, but city technology workers were troubleshooting the 911 system's computers with Verizon to identify and fix the breakdown Monday night.
Connor Scott, a spokesman for the Baltimore Office of Emergency Management, said Tuesday morning officials were still waiting to hear information on what caused the problem from Verizon. There have been no issues since the fix late Monday night, Scott said.
A spokeswoman for the phone company did not immediately respond to requests for comment Monday night.
Problems first arose about 5 p.m., Brillman said, and while some callers did not experience problems, some waited for more than a minute to reach a dispatcher. Officials did not know the average wait time callers were facing.
Brillman said the city followed a contingency plan it created for such issues, which have happened at other call centers in the past. He would not elaborate on what the plan involved.
The city's emergency call center, which is at Police Department headquarters downtown, receives about 3,800 calls on a normal night. The city did not add additional dispatchers to answer phones, instead focusing on fixing the technology, mayor's office spokesman Kevin Harris said.
"The issue is not having more people, it's the call getting through," Harris said. "They're working with computers. Sometimes there are glitches and errors."
Baltimore police spokesman Lt. Eric Kowalczyk asked the public to follow the police and fire departments' Twitter accounts for updates during the incident.
Baltimore Sun reporter Carrie Wells contributed to this report.