Last Updated Mar 22, 2018 6:33 PM EDT
ATLANTA -- City officials say Atlanta is dealing with a cyberattack that is holding internal systems hostage using ransomware, CBS affiliate WGCL-TV reports. Around 5 a.m., a written communication from the hackers warned that they had frozen the city's computer systems, CBS News homeland security correspondent Jeff Pegues reports.
The attack caused outages on several computer systems. Online bill paying services and some law enforcement data was unavailable.
According to WGCL-TV, a ransom note demanding payment in the cryptocurrency bitcoin was discovered Thursday morning. The letter states that all files had been encrypted, and require a key to regain access.
Atlanta Mayor Keisha Lance Bottoms tells CBS News the city is receiving assistance from the FBI, Department of Homeland Security (DHS), Microsoft and Cisco Security.
"We are aware of the situation and have offered our technical expertise and support to the city of Atlanta, as is standard practice for any of our public or private sector partners," DHS officials said in a statement. "Information shared with the department for cybersecurity purposes is confidential, and so we defer to the city to discuss details of its networks."
City sent a tweet in response to the incident, which reads in part: "The City of Atlanta is currently experiencing outages on various customer-facing applications, including some that customers may use to pay bills or access court-related information."
It remains unclear whether personal information had been compromised.
Pegues reports authorities are encouraging city employees to be on the lookout for signs that their data may have been stolen, like unexpected credit card charges. Atlanta's City Hall may be shut down Friday due to the ransomware attack.
A massive cyberattack in May 2017 crippled computer systems in more than 150 countries around the world. Known as the, the criminals demanded payment in order to unlock encrypted files. The attack used a tool developed by the National Security Agency that exploited a vulnerability in older Windows systems that had since been patched.
The White Housefor the WannaCry attack.