By Derek Draplin | The Center Square

The federal government has launched an investigation into mysterious drones that have been spotted on several occasions flying in eastern Colorado and parts of Nebraska.

Eyewitnesses have said the drones fly in formation at night a couple hundred feet in the air and have wingspans around six-feet. 

It’s still unknown who’s operating the drones or why, prompting an investigation by the Federal Aviation Administration.

U.S. Sen. Cory Gardner, R-Colorado, said in a statement this week that the agency has opened an investigation into the sightings. The Washington Post confirmed the investigation on Thursday. 

“I’ve been in contact with the FAA and I’m encouraged that they’ve opened a full investigation to learn the source and purpose of the drones,” Gardner said. “I will continue to closely monitor the situation.”

The Lincoln County Sheriff’s Office said last week it received reports of the drones, and law enforcement in Washington County has been in contact with the FAA regarding the sightings.

“We agree this is not common for our area, and are working diligently to try and identify them. We will be coordinating with other local sheriff's, and the FAA to figure this out as soon as possible,” the Washington County Sheriff’s Office said.

Sedgwick County Sheriff Carlton Britton said Thursday the drones have so far operated within federal guidelines and advised residents not to shoot at the drones.

Last month, the FAA proposed a rule to create a remote identification system so drones could be tracked.