Besides the city's website, fortlauderdale.gov, the police department website, flpd.org, also was affected, as was the city's email system.

City officials said Monday evening that once they became aware of the denial-of-service attack, which created a Web traffic jam and kept people from accessing the sites, the city shut them down as a precaution. City Manager Lee Feldman said it was like "a school going into lockdown" to make sure no one entered the site for malicious purposes.

Mayor Jack Seiler said the city sites had not been breached and that the city restored its online systems around 6:30 p.m.

However, some attempts to access the city's sites Monday night were unsuccessful. While city officials said no critical services were affected, people seeking to pay utility bills or looking for other government information were out of luck.

Seiler warned that there could be additional denial-of-service attacks in the coming days or a need for the city to shut down its sites to take additional safety measures. City officials said they have notified state and federal authorities of the incident.

By Sun Sentinel @SunSentinel

Cyber Monday became Cyber Attack Monday as the hacker group Anonymous made good on a threat to crash the city's website because of recent laws the city has passed regulating homeless behavior.