DALLAS >> Dallas officials are working with T-Mobile engineers to determine what’s prompting a flood of ghost calls that’s forced hundreds of 911 calls to be placed on hold and may have slowed the emergency response to two people who died.

Dallas resident David Taffet confronted Mayor Mike Rawlings at a news conference Wednesday to say it took 20 minutes to get through to 911 after his husband stopped breathing last week. At one point, Taffet was disconnected. He was placed on hold when he called back. Paramedics promptly arrived after he finally got through, but his husband later died at a hospital.

“I was just doing chest compressions on my husband and the call just dropped. I had to call back,” said Taffet, who at one point asked of the mayor, “How many others died?”

Rawlings said he apologized to the mother of a 6-month-old child who died during the weekend after falling from a bed. The child’s baby sitter tried calling 911 three times but kept being placed on hold.

Officials say phantom calls are coming into 911 from T-Mobile phones, leading to long wait times and delays in emergency response.

City Manager T.C. Broadnax said at one point last week the city had 360 calls on hold. The problem began in October and officials thought it had been resolved in January when they no longer saw a spike in the phantom calls, Broadnax said.

The city this week is increasing staffing levels at its 911 center and authorizing overtime shifts to ensure calls are being answered.

Rawlings said the problem means the city isn’t performing one of its core functions: ensuring people’s safety.

“As you can well imagine this situation is very frustrating,” he said, adding, “This is the No. 1 priority we’re facing right now as a city.”

Neville Ray, T-Mobile’s chief technology officer, said the company, which is based in Bellevue, Washington, hasn’t seen a similar problem anywhere else in the country.

“Clearly we are seeing a set of circumstances in Dallas which are unique,” he said.

Officials say engineers will examine how T-Mobile cellular technology and the city’s 911 infrastructure interact with each other. Rawlings said one consideration is that the problem could be on the city 911 system’s end.

T-Mobile says its team will remain in Dallas until the matter is resolved.

A state report released in 2014 by the Commission on State Emergency Communications notes 911 service will erode as new digital technology is introduced. The report says that’s because existing 911 systems in Texas and other states are “based on wireline technologies established decades ago.”

The phantom calls are happening at the same time Dallas-based AT&T experienced its own 911 problems. AT&T cellphone customers in Texas and other states were unable to call 911 for a time on March 8. The company has not explained the cause of the disruption.