Verizon released a statement after more than 100,000 outages were reported across the country on its wireless carrier network Monday morning.

“We are aware of an issue impacting service for some customers,” Verizon said in a statement to NBC News. “Our technicians are engaged and we are working quickly to identify and resolve the issue.”

The statement comes about three hours after the site Downdetector began receiving an influx of reports of Verizon outages in Chicago and beyond.

As of 9:30 a.m., Downdetector showed more than 4,000 Verizon outages in the Chicago area. Around 10:30 a.m., the number of reports had dropped to about 2,700, the site showed.

Nationally, the site showed more than 105,000 Verizon outages as of 10:30 a.m. An outage map from Downdetector Monday showed the “most reported” outage locations: Chicago, Indianapolis, Minneapolis, Phoenix, Omaha, Cincinnati, Denver, Seattle and Columbus.

Dozens of comments on the site from Verizon users said their phones were showing “SOS” mode on and off, leaving some unable to send or answer text messages or make calls.

Other comments on Verizon’s social media pages also pointed out that Verizon phones were in SOS mode.

The carrier responded to some comments and sometimes asked for more specific information from those who reported their phone in SOS.

“I know I would share your concerns if my phone was also on SOS,” said one of Verizon’s responses. “I’m here to investigate this and help find a solution. When did this problem first start? Can you share the nearest cross streets and city where this is happening? Please DM.”

What is SOS mode?

According to Apple, the SOS message appears when “your device is not connected to your mobile network,” but it also means you can make emergency calls over other carriers’ networks.

The feature is only available in the US, Australia and Canada.

“If SOS appears in the status bar of your iPhone, it means a cellular network is available for emergency calls,” the company says.

Anyone who calls with SOS automatically goes to a local emergency number and shares their location with the emergency services.

Users can also set their phones so that after they make an SOS emergency call, their phone will alert emergency contacts with a text message with their current location – and update those contacts if that location changes.

“On iPhone 14 or later (all models), you can even use Emergency SOS via satellite to text emergency services when cell and Wi-Fi coverage isn’t available,” Apple states.

This is a developing news story that will be updated.