Residents in four states experienced 911 outages on Wednesday amid warnings of cyberattacks.

However, 911 call lines were restored Wednesday evening following the disruptions across the entire state of South Dakota and areas of Nebraska, Nevada, and Texas, Reuters reported on Thursday.

The outlet noted that officials with the U.S. Federal Communications Commission are investigating what caused the incident.

South Dakota authorities, law enforcement in Las Vegas, officials with Nebraska’s Douglas County, and city officials in Del Rio, Texas, reported the outages.

In an announcement, police in Del Rio said, “We are aware of an outage with a major cellular carrier affecting the ability to reach 911.”

“This issue is with the carrier and not the city of Del Rio systems,” the agency explained, according to Today.

Authorities in Las Vegas later announced their 911 service was back up and running, noting that everyone who called during the outage had their call returned and were offered help.

Officials in South Dakota also said their services were restored. During the outage, the state’s officials told residents to call their county sheriff’s office administrative numbers in an emergency, according to KCAU:

The outlet also noted that “texting 911 does still go through, so you can do that.”

The Reuters article continued:

The Department of Homeland Security has warned of increased risks of cyber attacks on 911 services as they have migrated to digital systems based on Internet Protocol standards.

Several cyberattacks targeting 911 systems have taken down the services in recent years, one of which, in 2017, paralyzed 911 centers in more than a dozen states.

In May 2023, the city of Dallas, Texas, experienced a ransomware attack that caused widespread service outages and affected 911 dispatch services, Breitbart News reported.

“The Royal ransomware gang has claimed responsibility for the cyber attack, which has left the Texas city scrambling to restore services and assess the full extent of the damage,” the article said.

When a huge AT&T network outage hit in February, many thousands of customers across the nation were left without cell service and were also unable to get online, Breitbart News reported at the time.

The outlet noted that “lesser outages in the Verizon and T-Mobile cell networks have also been widely reported.”