A United Airlines flight from Hawaii to Los Angeles was forced to return to Honolulu after a “potential security concern” was discovered onboard. According to KTLA, Flight UA1169 departed Daniel K. Inouye International Airport at 9:40 p.m. Tuesday but turned around roughly 90 minutes later.

The flight landed safely back in Honolulu at 1:35 a.m. Wednesday, according to the Federal Aviation Administration (FAA).

A United spokesperson told KTLA the message was considered a “potential security concern,” though the specific contents were not revealed. Upon landing, law enforcement inspected the aircraft. Officials have not confirmed whether anything suspicious was found.

“We are rebooking customers on another flight to Los Angeles that departs later this evening,” the spokesperson said Wednesday morning.

The Boeing 777 was carrying 339 passengers and 10 crew members. The incident came to light on the same day a passenger on a Hawaiian Airlines flight from San Diego to Honolulu was arrested for an alleged bomb threat.

A Port of San Diego Harbor Police Department spokesperson confirmed to KTLA’s sister station KSWB/KUSI that a flight attendant had alerted the captain about a passenger claiming there was a bomb onboard. Authorities conducted a search but found “nothing suspicious.” Passengers eventually departed about six hours after their initially scheduled time.