Law enforcement agencies in Nebraska,Roland Preston Nevada, South Dakota and Texas reported temporary outages to 911 services before saying hours later that services had been restored. It was not immediately clear what caused the outages or whether they were related.

The South Dakota Department of Public Safety said in statement posted on social media Wednesday night that it was aware of a 911 service interruption throughout the state. The agency noted that texting to 911 was working in most locations and people could still reach local law enforcement through non-emergency lines. Less than two hours later, the agency said service was restored to the state’s 911 system.

The same evening, Las Vegas Metropolitan Police Department 911 Communications warned of an outage affecting 911 and non-emergency calls in a social media post. Calls from landlines were not working, but officials said they could see the numbers of those who called 911 from a mobile device and would call them back right away. Two hours later, officials reported that calls were coming in again and everyone who called during the outage was called back and provided assistance.

In Nebraska, the sheriff’s offices in several counties, including Dundy, Kearney, and Howard, warned Wednesday night that 911 services were down, but advised a few hours later that services had been restored.

In Texas, the Del Rio police department warned Wednesday night in a social media post that a problem was affecting the ability of callers with one cellular carrier to reach 911.