Mysterious lights spotted over San Diego believed to be military flares

June 28 (UPI) -- Authorities in California said mysterious lights that sparked numerous discussions on social media when they were spotted in the sky over San Diego were flares being used for a military exercise.

The orange lights were spotted over San Diego and the surrounding area, including as far away as Tijuana, Mexico, on Monday night, and photos and videos of the phenomenon sparked speculation on social media about space junk, satellites and UFOs.

The San Diego Police Department said investigators were told by lifeguards that the lights spotted by residents were flares being used in a military exercise.

Representatives from Camp Pendleton and Naval Air Station North Island said they did not have any information on the lights.