The MTA is wiring subway stations for cell phone use - but officials don’t want riders to make calls during the most extreme emergencies because they fear the calls could trigger explosive devices.

“In the immediate aftermath of an incident, our employees need the full attention of our customers to ensure the fastest and safest communication of information and potential evacuation,” MTA spokesman Jeremy Soffin said.

“We also exercise extreme caution in limiting use of any electronic device that could potentially serve as an accidental detonator during such an incident.”

Riders in stations during emergencies, regardless of the severity, should also refrain from calling 911 if there’s reason to believe police and firefighters already have been alerted so the emergency call system is not overwhelmed, Soffin said.

“These are situations when there is clearly an MTA employee responding and communicating with emergency responders,” Soffin said.

Last month, the MTA awarded a contract to wire 277 underground stations for cell phone service. Six stations are to be wired within a two-year pilot program. The rest of the system is expected to be completed over the next four years.

The first wave of “front-line” MTA workers have begun going through a new counterterrorism training course called Security Awareness.

The curriculum was developed by the National Transportation Institute, the MTA, the federal Department of Homeland Security and the EAI security corporation.