Flights scheduled to depart from the busiest airport in Britain were temporarily suspended Tuesday amid a reported drone sighting near the runways -- less than three weeks after a similar incident in the area caused chaos during the Christmas travel period.

The suspension -- which lasted around an hour -- at London Heathrow Airport on Tuesday came as police have still not yet found the person or persons responsible for flying drones around Gatwick Airport in late December.

“We are responding to a drone sighting at Heathrow and are working closely with the Met Police to prevent any threat to operational safety,” the airport had said in a statement. “As a precautionary measure, we have stopped departures while we investigate. We apologize to passengers for any inconvenience this may cause.”

The airport later reopened its runways, according to Sky News.

Sussex Police Chief Giles York, who is working on the Gatwick investigation, told BBC radio in late December that police have searched 26 potential launch sites near the airport but do not believe they have found the drone that was seen near the runway on Dec. 19 and Dec. 20.

York said he is "absolutely certain that there was a drone flying throughout the period that the airport was closed."

A senior detective also said at one point it was possible drones hadn't flown over the airport, sowing confusion, but police later insisted the drone sightings were authentic.

That claim drew a sharp rebuke from government ministers, who in a conference call described it as a “mess-up” and said police "have not handled their communication response well.”

Gatwick’s closure led to more than 100,000 people being stranded or delayed in the worst ever drone-related disruption at an international airport.

No one has been found responsible despite the deployment of military assets to track and deter drone flights.

The Associated Press contributed to this report.