EL PASO, Texas -- Concerns are reaching to the highest government levels in the U.S and Mexico to have a critical issue fixed to prevent a possible disaster.
Right now, Verizon is experiencing problems, but other cell phone carriers, like AT&T, could also be affected.
In a letter, U.S. Sen. Ted Cruz (R-Texas) wrote on August 18th to the chairman of the Federal Communications Commission and to the U.S. Secretary of State about a Mexican telecommunications carrier that "can and will cause harmful interference with U.S. networks, including those used by federal and local law enforcement, hospitals, military, and other sensitive and important users."
According to El Paso city Rep. Henry Rivera, his office is experiencing dropped calls.
"If you're trying to call for assistance, whether it be medical or police, and there are dropped calls, that's very dangerous. We're talking about lives here," said Rivera.
Rivera is a retired police officer. His family and staff have all experienced what they say is an unusually high number of dropped calls using Verizon.
His satellite office is just a few miles away from the Cielo Vista Walmart memorial. "From here to the memorial, just down there to Cielo Vista mall, the calls wouldn't go through," explained Rivera.
In Cruz's letter, he says a new telecommunications carrier in Mexico, named Altán could be to blame. He noted that Altan uses the same power frequency as U.S. carriers, potentially interfering with signals here in El Paso.
Cruz says Altan tested its signal on August 5th, just two days after the tragic mass shooting at the Cielo Vista Walmart.
"The result was a severe degradation of the communications network in El Paso, including a nearly complete loss of wireless network coverage for University Medical Center, where more than 10 people injured in the shooting, five of which were in critical condition at the time, were being treated," Cruz wrote.
However, a spokesman with University Medical Center says the hospital did not experience any disruption in services. If anything, the spokesman said some users may have seen some dropped calls.
El Paso Mayor Dee Margo also sent a letter to the FCC on September 25th saying both the city's police and fire departments reported issues with connectivity.
"Police officers are unable to pull up critical data and throughput equipment in patrol cars along the border has slowed. Emergency medical technicians equipment used to share patient information have lost connectivity," said Margo.
El Paso Fire Chief Mario D'Agostino also submitted a report to the FCC detailing the extent of interference, of which ABC-7 obtained a copy.
It details dates when the city's staff reported communications interference.
One of those reports from carrier Motorola describes the interference as causing in-bound calls not to process, be garbled or not allow subscribers onto the system.
Another incident on September 3rd indicates "signaling of floor noise coming from the south Juarez, Mexico."
According to city staff, "The floor noise means the minimum amount of radio frequency noise allowed to transmit and receive not to cause interference."
The telecommunications controversy, which has reached high levels of both Mexico and U.S. federal governments, has led to finger pointing.
In a statement, a spokesman with Altan tells ABC 7: "The situation experienced in the border is caused by the activity in the united states' mobile carriers in the 700 mhz band spectrum interfering on the Mexico side (them radiating service into Mexico) as Altan is not radiating service into the U.S. territory."
The FCC assured Cruz in late August that they are working with Mexico to resolve the situation. But the FCC has not reported back to the city of El Paso about any improvements to the systems.
However, a spokesman with the city tells ABC-7 the city has not seen any further interference since they were last contacted by the FCC.
Locally, the FCC let city officials know they contacted three U.S. carriers on September 24th -- ATT&T, Verizon and Nextel, which merged with Sprint -- to determine the extent of wireless interruptions.
Verizon officials say if their customers experience any wireless issues, they should contact Verizon customer service.