A Colorado sheriff on Wednesday rescinded his call for people to be on the lookout for a “command vehicle” that may be operating mysterious groups of drones spotted in recent weeks over northeastern Colorado and western Nebraska.

That request for public assistance “is no longer pertinent or relevant," the Phillips County Sheriff's Office said on Facebook.

However, a person who was at Monday's closed-door meeting between law enforcement and government officials attended by Sheriff Thomas Elliott said authorities were never looking for such a vehicle.

Nobody has claimed responsibility for the mysterious nighttime flights of groups of six to 10 drones in grid-like patterns since December, which prompted the Monday meeting in northeastern Colorado.

The sheriff's original statement said a task force had been organized to investigate the flights, and it was asking for the public's assistance in finding the command vehicle operating the drones.

The statement said the vehicle could be a closed-box trailer with antennas or a large van that seems out of place.

On Wednesday, another person who attended that meeting said no such call for public assistance was discussed .

“The working group was never looking for a command vehicle as described in the recent social media post,” said the official, who requested anonymity because the person did not want to publicly contradict the sheriff's statement.

Wednesday's updated Facebook post did not explain why the information provided previously about the command vehicle was no longer relevant.

Elliott was traveling to a conference and unavailable to comment, said Phillips County Sheriff's Office Administrative Assistant Kelley Sullivan.

She said the sheriff was trying to be helpful with his original post by relaying what he believed he had heard in the meeting. The sheriff asked her to post the update Wednesday following a query for more information about the command vehicle from The Associated Press.

Republican state Sen. Jerry Sonnenberg, who represents a swath of the territory in northeastern Colorado where the drones have been spotted, defended the efforts of Elliott and other officials to respond to citizens' concerns.

“We are worried about people invading our privacy,” Sonnenberg said.

U.S. Transportation Secretary Elaine Chao cited the mysterious drone flights on Wednesday as evidence of the need for an proposed agency rule to allow the Federal Aviation Administration and other authorities to remotely identify drones. The proposal would require all drones that weigh over half a pound (0.2 kilograms) to register with the FAA.

“Recent news reports out of Colorado and Nebraska of mystery drones flying in formations at night is a timely illustration of why remote ID's are needed,” Chao said at the Consumer Electronics Show in Las Vegas, according to prepared remarks.

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Associated Press writer James Anderson in Denver contributed to this report.