PROVIDENCE — Sewer-system operator Narragansett Bay Commission said Wednesday that it paid a quarter-million-dollar ransom to end a cyberattack against its computer systems.

"The NBC resolved the situation with a $250K negotiated payment," commission spokeswoman Jamie R. Samons said in an email to The Providence Journal Wednesday. "After payment, NBC was able to bring its systems back on-line in a matter of hours."

On Friday, when the commission first disclosed the attack, Samons said the attackers encrypted the data on commission computer systems, but not those that run the sewage-treatment plants. "There has been no disruption to wastewater collection and treatment services," she wrote.

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In ransomware attacks, hackers encrypt data on a victim's computer system and refuse to supply the key to decode the data and make it usable until a ransom is paid.

"Last week, the Narragansett Bay Commission identified a cybersecurity incident that involved the encryption of data on certain computers and systems in its network," Samons wrote on Friday.

The commission runs sewer systems in parts of the metropolitan Providence and Blackstone Valley areas.

This article originally appeared on The Providence Journal: Narragansett Bay Commission paid $250,000 to end cyberattack