Hours after a widespread 911 outage hit four states in the US, a deliberate cut to an AT&T fiber cable cut led to travel disruption at Sacramento airport.

The outage early yesterday morning in California has been blamed on a cut to a fiber cable, lasting for several hours.

The outage was noted at around 6:30 am local time before services were restored just after 11:30 am.

"We've restored Internet and wireless service to affected customers in the Sacramento International Airport area following a fiber cut which appears to be an act of vandalism or attempted theft. We appreciate the patience of our customers as we worked to make repairs as quickly as possible," AT&T said in a statement.

The outage meant that several flights were delayed, with Southwest Airlines staff unable to connect to the Internet.

It's reported that the cable was cut at 1:30 am, at which time investigators responded to the area.

The Sacramento County Sheriff’s Office has launched an investigation into the outage.

According to the New York Times, the cable was attached to a pole about 2.5 miles from the airport, and had been slashed in one place about four or five feet from the ground in a manner that was "very deliberate" and "very targeted."

In February, AT&T was hit by a widespread outage which meant its first emergency services network FirstNet was out of service.

Earlier in the day, an outage impacting 911 calls affected all of South Dakota, plus parts of Nebraska, Nevada, and Texas. The cause of the outage is not yet known.