DALLAS -- The Dallas City Council is set to discuss more details on the weekend hack of emergency sirens at its Wednesday morning meeting. 

The item is an emergency addendum. The council will discuss whether to add $100,000 to the existing contract with the company that repairs and maintains the sirens, West Shore Services, Inc. The money would go toward security enhancements and increase the cost of the six-year contract from $567,368 to $667,368. 

All 156 sirens in Dallas went off late Friday night into Saturday morning, sounding off and on for about 90 minutes. 

Investigators believe someone who lives in North Texas used radio frequencies to set the sirens off. The Dallas Police Department is working with the FBI to investigate. 

City Manager T.C. Broadnax told reporters Monday that the system is safe and the gaps that allowed the hack had been closed, but that the system is old and needs an upgrade to make sure it isn't vulnerable to future attacks. 

You can view the supplemental agenda item here.

We will add updates to this story as we get them.