(Reuters) – Atlanta’s top officials holed up in their offices on Saturday as they worked to restore critical systems knocked out by a nine-day-old cyber attack that plunged the Southeastern U.S. metropolis into technological chaos and forced some city workers to revert to paper.

On an Easter and Passover holiday weekend, city officials labored in preparation for the workweek to come.

Police and other public servants have spent the past week trying to piece together their digital work lives, recreating audit spreadsheets and conducting business on mobile phones in response to one of the most devastating “ransomware” virus attacks to hit an American city.

Three city council staffers have been sharing a single clunky personal laptop brought in after cyber extortionists attacked Atlanta’s computer network with a virus that scrambled data and still prevents access to critical systems.

“It’s extraordinarily frustrating,” said Councilman Howard Shook, whose office lost 16 years of digital records.

One compromised city computer seen by Reuters showed multiple corrupted documents with “weapologize” and “imsorry” added to file names.

Ransomware attacks have surged in recent years as cyber extortionists moved from attacking individual computers to large organizations, including businesses, healthcare organizations and government agencies. Previous high-profile attacks have shut down factories, prompted hospitals to turn away patients and forced local emergency dispatch systems to move to manual operations.

Ransomware typically corrupts data and does not steal it. The city of Atlanta has said it does not believe private residents’ information is in the hands of hackers, but they do not know for sure.

City officials have declined to discuss the extent of damage beyond disclosed outages that have shut down some services at municipal offices, including courts and the water department.

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