(AP) — Wichita’s city manager says the city’s electronic procurement website was the recent victim of a “sophisticated hacking operation.”

City Manager Robert Layton also said Tuesday the FBI is working with city officials to determine what information was taken and how similar breaches can be prevented in the future.

Officials also say the breach may have affected as many as 29,000 vendors and employees and that Social Security numbers, taxpayer identification numbers and banking information may have been compromised.

Wichita police Capt. Gavin Seiler said the hacking occurred sometime over the weekend. He says as soon as city officials discovered the attack they shut down the system and notified authorities.