LONDON (AP) — London’s Gatwick Airport closed its runway for almost an hour Sunday after a drone was reported nearby.

Officials at Britain’s second-busiest airport said 12 incoming flights had to be diverted to other airports.

The airport said that “following established procedures, operations at London Gatwick were suspended temporarily” at 1:44 p.m. “while investigations into the sighting of a suspected drone close to the airfield took place.”

The airport reopened about 50 minutes later. A Gatwick spokesperson was unable to say whether a drone had been discovered.

In December 2018, more than 140,000 travelers were stranded or delayed after dozens of drone sightings shut down Gatwick for parts of three consecutive days.

A months-long police investigation failed to identify the culprits or determine how many of the sightings were real. Police said at the time that the incident was not deemed terror-related “and there is no evidence to suggest it was either state-sponsored, campaign or interest-group led.”