A ransomware attack on the city of Dallas has compromised several servers and impacted city services, officials said Thursday, May 4.

The attack, which the city’s Security Operations Center detected Wednesday morning, was launched by a group called Royal, according to a city statement. As of Thursday afternoon, the city’s IT department and its vendors said they have isolated the issue and are working to gradually restore service.

“Employees have been hard at work to contain the issue and ensure continued service to our residents,” City Manager T.C. Broadnax said in a statement Thursday morning. “While the source of the outage is still under investigation, I am optimistic that the risk is contained.”

As of Thursday afternoon, the network appeared to still be down. A notice on the city of Dallas' website stated, “the city is experiencing a service outage and is working to restore services.” Updates will be posted on the city’s Twitter account.

Dallas Police and Dallas Fire Rescue services to residents, including 911 calls, were not impacted by the ransomware attack. Calls to the city’s 311 helpline are being answered, but nonemergency service requests could be delayed, according to a press release.

City meeting notices and livestreams are available at http://dallascityhall.webex.com and www.dallascitynews.net/watch-live, plus Spectrum channels 16 and 95, and AT&T U-verse at 99, according to the press release.

Dallas Public Library branches will remain open during their usual hours, but online materials are unavailable, according to the release. Dallas Water Utilities billing was unaffected as of Thursday morning, but meter reading will be delayed.

The ransomware attack will not affect the general election May 6, and election results will be posted by the Dallas County Elections Department.

Chief Information Officer Bill Zielinski is scheduled to brief the city’s Public Safety Committee about the ransomware attack May 8.

Editors note: This article has was updated with the latest information from the city of Dallas.